diff --git a/app/api/repp/api.rb b/app/api/repp/api.rb
index 9c12470a0..7858cd625 100644
--- a/app/api/repp/api.rb
+++ b/app/api/repp/api.rb
@@ -59,5 +59,6 @@ module Repp
     mount Repp::AccountV1
     mount Repp::DomainTransfersV1
     mount Repp::NameserversV1
+    mount Repp::DomainContactsV1
   end
 end
diff --git a/app/api/repp/domain_contacts_v1.rb b/app/api/repp/domain_contacts_v1.rb
new file mode 100644
index 000000000..2d2cc4dbb
--- /dev/null
+++ b/app/api/repp/domain_contacts_v1.rb
@@ -0,0 +1,35 @@
+module Repp
+  class DomainContactsV1 < Grape::API
+    version 'v1', using: :path
+
+    resource :domains do
+      resource :contacts do
+        patch '/' do
+          predecessor = current_user.registrar.contacts.find_by(code: params[:predecessor])
+          successor = current_user.registrar.contacts.find_by(code: params[:successor])
+
+          unless predecessor
+            error!({ error: { type: 'invalid_request_error',
+                              param: 'predecessor',
+                              message: "No such contact: #{params[:predecessor]}" } }, :bad_request)
+          end
+
+          unless successor
+            error!({ error: { type: 'invalid_request_error',
+                              param: 'successor',
+                              message: "No such contact: #{params[:successor]}" } }, :bad_request)
+          end
+
+          if predecessor == successor
+            error!({ error: { type: 'invalid_request_error',
+                              message: 'Successor contact must be different from predecessor' } },
+                   :bad_request)
+          end
+
+          affected_domains, skipped_domains = TechDomainContact.replace(predecessor, successor)
+          @response = { affected_domains: affected_domains, skipped_domains: skipped_domains }
+        end
+      end
+    end
+  end
+end
diff --git a/app/controllers/registrar/bulk_change_controller.rb b/app/controllers/registrar/bulk_change_controller.rb
new file mode 100644
index 000000000..562344a46
--- /dev/null
+++ b/app/controllers/registrar/bulk_change_controller.rb
@@ -0,0 +1,20 @@
+class Registrar
+  class BulkChangeController < DeppController
+    helper_method :available_contacts
+
+    def new
+      authorize! :manage, :repp
+      render file: 'registrar/bulk_change/new', locals: { active_tab: default_tab }
+    end
+
+    private
+
+    def available_contacts
+      current_user.registrar.contacts.order(:name).pluck(:name, :code)
+    end
+
+    def default_tab
+      :technical_contact
+    end
+  end
+end
diff --git a/app/controllers/registrar/registrar_nameservers_controller.rb b/app/controllers/registrar/nameservers_controller.rb
similarity index 94%
rename from app/controllers/registrar/registrar_nameservers_controller.rb
rename to app/controllers/registrar/nameservers_controller.rb
index 1af3cde64..b6f7af829 100644
--- a/app/controllers/registrar/registrar_nameservers_controller.rb
+++ b/app/controllers/registrar/nameservers_controller.rb
@@ -1,9 +1,5 @@
 class Registrar
-  class RegistrarNameserversController < DeppController
-    def edit
-      authorize! :manage, :repp
-    end
-
+  class NameserversController < BulkChangeController
     def update
       authorize! :manage, :repp
 
@@ -52,7 +48,7 @@ class Registrar
         redirect_to registrar_domains_url
       else
         @api_errors = parsed_response[:errors]
-        render :edit
+        render file: 'registrar/bulk_change/new', locals: { active_tab: :nameserver }
       end
     end
   end
diff --git a/app/controllers/registrar/tech_contacts_controller.rb b/app/controllers/registrar/tech_contacts_controller.rb
new file mode 100644
index 000000000..fccb10f78
--- /dev/null
+++ b/app/controllers/registrar/tech_contacts_controller.rb
@@ -0,0 +1,58 @@
+class Registrar
+  class TechContactsController < BulkChangeController
+    def update
+      authorize! :manage, :repp
+
+      uri = URI.parse("#{ENV['repp_url']}domains/contacts")
+
+      request = Net::HTTP::Patch.new(uri)
+      request.set_form_data(predecessor: params[:predecessor], successor: params[:successor])
+      request.basic_auth(current_user.username, current_user.password)
+
+      if Rails.env.test?
+        response = Net::HTTP.start(uri.hostname, uri.port,
+                                   use_ssl: (uri.scheme == 'https'),
+                                   verify_mode: OpenSSL::SSL::VERIFY_NONE) do |http|
+          http.request(request)
+        end
+      elsif Rails.env.development?
+        client_cert = File.read(ENV['cert_path'])
+        client_key = File.read(ENV['key_path'])
+        response = Net::HTTP.start(uri.hostname, uri.port,
+                                   use_ssl: (uri.scheme == 'https'),
+                                   verify_mode: OpenSSL::SSL::VERIFY_NONE,
+                                   cert: OpenSSL::X509::Certificate.new(client_cert),
+                                   key: OpenSSL::PKey::RSA.new(client_key)) do |http|
+          http.request(request)
+        end
+      else
+        client_cert = File.read(ENV['cert_path'])
+        client_key = File.read(ENV['key_path'])
+        response = Net::HTTP.start(uri.hostname, uri.port,
+                                   use_ssl: (uri.scheme == 'https'),
+                                   cert: OpenSSL::X509::Certificate.new(client_cert),
+                                   key: OpenSSL::PKey::RSA.new(client_key)) do |http|
+          http.request(request)
+        end
+      end
+
+      parsed_response = JSON.parse(response.body, symbolize_names: true)
+
+      if response.code == '200'
+        notices = [t('.replaced')]
+
+        notices << "#{t('.affected_domains')}: #{parsed_response[:affected_domains].join(', ')}"
+
+        if parsed_response[:skipped_domains]
+          notices << "#{t('.skipped_domains')}: #{parsed_response[:skipped_domains].join(', ')}"
+        end
+
+        flash[:notice] = notices
+        redirect_to registrar_domains_url
+      else
+        @error = parsed_response[:error]
+        render file: 'registrar/bulk_change/new', locals: { active_tab: :technical_contact }
+      end
+    end
+  end
+end
diff --git a/app/models/tech_domain_contact.rb b/app/models/tech_domain_contact.rb
index 68ae35dde..55cc45aed 100644
--- a/app/models/tech_domain_contact.rb
+++ b/app/models/tech_domain_contact.rb
@@ -1,2 +1,23 @@
 class TechDomainContact < DomainContact
+  # Audit log is needed, therefore no raw SQL
+  def self.replace(predecessor, successor)
+    affected_domains = []
+    skipped_domains = []
+    tech_contacts = where(contact: predecessor)
+
+    transaction do
+      tech_contacts.each do |tech_contact|
+        if tech_contact.domain.discarded?
+          skipped_domains << tech_contact.domain.name
+          next
+        end
+
+        tech_contact.contact = successor
+        tech_contact.save!
+        affected_domains << tech_contact.domain.name
+      end
+    end
+
+    return affected_domains.sort, skipped_domains.sort
+  end
 end
diff --git a/app/views/admin/base/_flash_messages.html.erb b/app/views/application/_flash_messages.html.erb
similarity index 77%
rename from app/views/admin/base/_flash_messages.html.erb
rename to app/views/application/_flash_messages.html.erb
index 4a10df304..9b31f0d3f 100644
--- a/app/views/admin/base/_flash_messages.html.erb
+++ b/app/views/application/_flash_messages.html.erb
@@ -1,7 +1,11 @@
 <% if flash[:notice] %>
     <div class="alert alert-success alert-dismissible">
         <button class="close" data-dismiss="alert" type=button><span>&times;</span></button>
-        <p><%= flash[:notice] %></p>
+        <% if flash[:notice].respond_to?(:join) %>
+            <p><%= flash[:notice].join('<br>').html_safe %></p>
+        <% else %>
+            <p><%= flash[:notice] %></p>
+        <% end %>
     </div>
 <% end %>
 
diff --git a/app/views/layouts/registrar/base.html.erb b/app/views/layouts/registrar/base.html.erb
index 6116c7a26..c1b67673e 100644
--- a/app/views/layouts/registrar/base.html.erb
+++ b/app/views/layouts/registrar/base.html.erb
@@ -39,7 +39,7 @@
     </div>
 </nav>
 <div class="container">
-    <%= render 'shared/flash' %>
+    <%= render 'flash_messages' %>
     <% if depp_controller? %>
         <%= render 'registrar/shared/epp_results' %>
     <% end %>
diff --git a/app/views/registrar/registrar_nameservers/_form.html.erb b/app/views/registrar/bulk_change/_nameserver_form.html.erb
similarity index 89%
rename from app/views/registrar/registrar_nameservers/_form.html.erb
rename to app/views/registrar/bulk_change/_nameserver_form.html.erb
index 3aca3e0e1..1b1900314 100644
--- a/app/views/registrar/registrar_nameservers/_form.html.erb
+++ b/app/views/registrar/bulk_change/_nameserver_form.html.erb
@@ -1,12 +1,13 @@
-<%= form_tag registrar_update_registrar_nameserver_path, method: :put, class: 'form-horizontal' do %>
+<%= form_tag registrar_nameservers_path, method: :patch, class: 'form-horizontal' do %>
+    <%= render 'registrar/domain_transfers/form/api_errors' %>
+
     <div class="form-group">
         <div class="col-md-2 control-label">
             <%= label_tag :old_hostname %>
         </div>
 
         <div class="col-md-5">
-            <%= text_field_tag :old_hostname, params[:old_hostname], autofocus: true,
-                               required: true,
+            <%= text_field_tag :old_hostname, params[:old_hostname], required: true,
                                class: 'form-control' %>
         </div>
     </div>
diff --git a/app/views/registrar/bulk_change/_tech_contact_form.html.erb b/app/views/registrar/bulk_change/_tech_contact_form.html.erb
new file mode 100644
index 000000000..24e7ff27f
--- /dev/null
+++ b/app/views/registrar/bulk_change/_tech_contact_form.html.erb
@@ -0,0 +1,48 @@
+<%= form_tag registrar_tech_contacts_path, method: :patch, class: 'form-horizontal' do %>
+    <% if @error %>
+        <div class="alert alert-danger">
+            <%= @error[:message] %>
+        </div>
+    <% end %>
+
+    <div class="form-group">
+        <div class="col-md-2 control-label">
+            <%= label_tag :predecessor %>
+        </div>
+
+        <div class="col-md-5">
+            <%= text_field_tag :predecessor, params[:predecessor],
+                               list: :contacts,
+                               required: true,
+                               autofocus: true,
+                               class: 'form-control' %>
+        </div>
+    </div>
+
+    <div class="form-group">
+        <div class="col-md-2 control-label">
+            <%= label_tag :successor %>
+        </div>
+
+        <div class="col-md-5">
+            <%= text_field_tag :successor, params[:successor],
+                               list: :contacts,
+                               required: true,
+                               class: 'form-control' %>
+        </div>
+    </div>
+
+    <div class="form-group">
+        <div class="col-md-5 col-md-offset-2 text-right">
+            <button class="btn btn-warning">
+                <%= t '.submit_btn' %>
+            </button>
+        </div>
+    </div>
+<% end %>
+
+<datalist id="contacts">
+    <% available_contacts.each do |data| %>
+        <option value="<%= data.second %>"><%= data.first %></option>
+    <% end %>
+</datalist>
diff --git a/app/views/registrar/bulk_change/new.html.erb b/app/views/registrar/bulk_change/new.html.erb
new file mode 100644
index 000000000..77cc2d20a
--- /dev/null
+++ b/app/views/registrar/bulk_change/new.html.erb
@@ -0,0 +1,32 @@
+<ol class="breadcrumb">
+    <li><%= link_to t('registrar.domains.index.header'), registrar_domains_path %></li>
+</ol>
+
+<div class="page-header">
+    <h1><%= t '.header' %></h1>
+</div>
+
+<div class="row">
+    <div class="col-md-10">
+        <ul class="nav nav-tabs">
+            <li class="<%= 'active' if active_tab == :technical_contact %>">
+                <a href="#technical_contact" data-toggle="tab"><%= t '.technical_contact' %></a>
+            </li>
+
+            <li class="<%= 'active' if active_tab == :nameserver %>">
+                <a href="#nameserver" data-toggle="tab"><%= t '.nameserver' %></a>
+            </li>
+        </ul>
+
+        <div class="tab-content">
+            <div class="tab-pane<%= ' active' if active_tab == :technical_contact %>"
+                 id="technical_contact">
+                <%= render 'tech_contact_form', available_contacts: available_contacts %>
+            </div>
+
+            <div class="tab-pane<%= ' active' if active_tab == :nameserver %>" id="nameserver">
+                <%= render 'nameserver_form' %>
+            </div>
+        </div>
+    </div>
+</div>
diff --git a/app/views/registrar/domains/index.html.erb b/app/views/registrar/domains/index.html.erb
index 319f0d04f..cbc048697 100644
--- a/app/views/registrar/domains/index.html.erb
+++ b/app/views/registrar/domains/index.html.erb
@@ -1,13 +1,13 @@
 <div class="page-header">
     <div class="row">
-        <div class="col-sm-7">
+        <div class="col-sm-5">
             <h1><%= t '.header' %></h1>
         </div>
 
-        <div class="col-sm-5 text-right">
+        <div class="col-sm-7 text-right">
             <%= link_to t('.new_btn'), new_registrar_domain_path, class: 'btn btn-primary' %>
             <%= link_to t('.transfer_btn'), new_registrar_domain_transfer_path, class: 'btn btn-default' %>
-            <%= link_to t('.replace_nameserver_btn'), registrar_edit_registrar_nameserver_path,
+            <%= link_to t('.bulk_change_btn'), new_registrar_bulk_change_path,
                         class: 'btn btn-default' %>
         </div>
     </div>
@@ -24,22 +24,22 @@
         <div class="table-responsive">
             <table class="table table-hover table-bordered table-condensed">
                 <thead>
-                    <tr>
-                        <th class="col-xs-2">
-                            <%= sort_link(@q, 'name') %>
-                        </th>
-                        <th class="col-xs-2">
-                            <%= sort_link @q, 'registrant_name', Registrant.model_name.human %>
-                        </th>
-                        <th class="col-xs-2">
-                            <%= sort_link @q, 'valid_to', Domain.human_attribute_name(:expire_time) %>
-                        </th>
-                        <th class="col-xs-2"></th>
-                    </tr>
+                <tr>
+                    <th class="col-xs-2">
+                        <%= sort_link(@q, 'name') %>
+                    </th>
+                    <th class="col-xs-2">
+                        <%= sort_link @q, 'registrant_name', Registrant.model_name.human %>
+                    </th>
+                    <th class="col-xs-2">
+                        <%= sort_link @q, 'valid_to', Domain.human_attribute_name(:expire_time) %>
+                    </th>
+                    <th class="col-xs-2"></th>
+                </tr>
                 </thead>
 
                 <tbody>
-                    <%= render @domains %>
+                <%= render @domains %>
                 </tbody>
             </table>
         </div>
diff --git a/app/views/registrar/registrar_nameservers/edit.html.erb b/app/views/registrar/registrar_nameservers/edit.html.erb
deleted file mode 100644
index 0903f1556..000000000
--- a/app/views/registrar/registrar_nameservers/edit.html.erb
+++ /dev/null
@@ -1,11 +0,0 @@
-<ol class="breadcrumb">
-    <li><%= link_to t('registrar.domains.index.header'), registrar_domains_path %></li>
-</ol>
-
-<div class="page-header">
-    <h1><%= t '.header' %></h1>
-</div>
-
-<%= render 'registrar/domain_transfers/form/api_errors' %>
-
-<%= render 'form' %>
diff --git a/config/locales/registrar/bulk_change.en.yml b/config/locales/registrar/bulk_change.en.yml
new file mode 100644
index 000000000..033d63e74
--- /dev/null
+++ b/config/locales/registrar/bulk_change.en.yml
@@ -0,0 +1,14 @@
+en:
+  registrar:
+    bulk_change:
+      new:
+        header: Bulk change
+        technical_contact: Technical contact
+        nameserver: Nameserver
+
+      tech_contact_form:
+        submit_btn: Replace technical contacts
+
+      nameserver_form:
+        ip_hint: One IP per line
+        replace_btn: Replace nameserver
diff --git a/config/locales/registrar/domains.en.yml b/config/locales/registrar/domains.en.yml
index ddd30676d..31380074f 100644
--- a/config/locales/registrar/domains.en.yml
+++ b/config/locales/registrar/domains.en.yml
@@ -5,7 +5,7 @@ en:
         header: Domains
         new_btn: New domain
         transfer_btn: Transfer
-        replace_nameserver_btn: Replace nameserver
+        bulk_change_btn: Bulk change
         csv:
           domain_name: Domain
           transfer_code: Transfer code
diff --git a/config/locales/registrar/nameservers.en.yml b/config/locales/registrar/nameservers.en.yml
new file mode 100644
index 000000000..fbe4c387e
--- /dev/null
+++ b/config/locales/registrar/nameservers.en.yml
@@ -0,0 +1,5 @@
+en:
+  registrar:
+    nameservers:
+      update:
+        replaced: Nameserver have been successfully replaced
diff --git a/config/locales/registrar/registrar_nameservers.en.yml b/config/locales/registrar/registrar_nameservers.en.yml
deleted file mode 100644
index b9e7cb2fa..000000000
--- a/config/locales/registrar/registrar_nameservers.en.yml
+++ /dev/null
@@ -1,13 +0,0 @@
-en:
-  registrar:
-    registrar_nameservers:
-      edit:
-        header: Replace nameserver
-        replace_btn: Replace
-
-      form:
-        ip_hint: One IP per line
-        replace_btn: Replace nameserver
-
-      update:
-        replaced: Nameserver have been successfully replaced
diff --git a/config/locales/registrar/tech_contacts.en.yml b/config/locales/registrar/tech_contacts.en.yml
new file mode 100644
index 000000000..bf57f0cc7
--- /dev/null
+++ b/config/locales/registrar/tech_contacts.en.yml
@@ -0,0 +1,7 @@
+en:
+  registrar:
+    tech_contacts:
+      update:
+        replaced: Technical contacts have been successfully replaced.
+        affected_domains: Affected domains
+        skipped_domains: Skipped domains
diff --git a/config/routes.rb b/config/routes.rb
index 9caeef4a2..099702346 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -62,9 +62,9 @@ Rails.application.routes.draw do
       end
     end
     resources :domain_transfers, only: %i[new create]
-    get 'registrar/nameservers', to: 'registrar_nameservers#edit', as: :edit_registrar_nameserver
-    put 'registrar/nameservers', to: 'registrar_nameservers#update', as: :update_registrar_nameserver
-
+    resource :bulk_change, controller: :bulk_change, only: :new
+    resource :tech_contacts, only: :update
+    resource :nameservers, only: :update
     resources :contacts, constraints: {:id => /[^\/]+(?=#{ ActionController::Renderers::RENDERERS.map{|e| "\\.#{e}\\z"}.join("|") })|[^\/]+/} do
       member do
         get 'delete'
diff --git a/doc/repp/v1/domain_contacts.md b/doc/repp/v1/domain_contacts.md
new file mode 100644
index 000000000..8a024e763
--- /dev/null
+++ b/doc/repp/v1/domain_contacts.md
@@ -0,0 +1,19 @@
+# Domain contacts
+
+## PATCH https://repp.internet.ee/v1/domains/contacts
+Replaces all domain contacts of the current registrar.
+
+### Example request
+```
+$ curl https://repp.internet.ee/v1/domains/contacts \
+   -X PATCH \
+   -u username:password \
+   -d predecessor=foo \
+   -d successor=bar
+```
+### Example response
+```
+{
+  "affected_domains": ["example.com", "example.org"]
+}
+```
diff --git a/test/fixtures/domain_contacts.yml b/test/fixtures/domain_contacts.yml
index 3442278a1..43d082e31 100644
--- a/test/fixtures/domain_contacts.yml
+++ b/test/fixtures/domain_contacts.yml
@@ -8,11 +8,26 @@ shop_william:
   contact: william
   type: TechDomainContact
 
+shop_acme_ltd:
+  domain: shop
+  contact: acme_ltd
+  type: TechDomainContact
+
 airport_john:
   domain: airport
   contact: john
   type: AdminDomainContact
 
+airport_william_admin:
+  domain: airport
+  contact: william
+  type: AdminDomainContact
+
+airport_william_tech:
+  domain: airport
+  contact: william
+  type: TechDomainContact
+
 library_john:
   domain: library
   contact: john
diff --git a/test/fixtures/nameservers.yml b/test/fixtures/nameservers.yml
index 8c3c021d6..344f7894d 100644
--- a/test/fixtures/nameservers.yml
+++ b/test/fixtures/nameservers.yml
@@ -18,6 +18,10 @@ airport_ns1:
   hostname: ns1.bestnames.test
   domain: airport
 
+airport_ns2:
+  hostname: ns2.bestnames.test
+  domain: airport
+
 metro_ns1:
   hostname: ns1.bestnames.test
   domain: metro
diff --git a/test/integration/api/domain_contacts_test.rb b/test/integration/api/domain_contacts_test.rb
new file mode 100644
index 000000000..c069bc23d
--- /dev/null
+++ b/test/integration/api/domain_contacts_test.rb
@@ -0,0 +1,103 @@
+require 'test_helper'
+
+class APIDomainContactsTest < ActionDispatch::IntegrationTest
+  def test_replace_all_tech_contacts_of_the_current_registrar
+    patch '/repp/v1/domains/contacts', { predecessor: 'william-001', successor: 'john-001' },
+          { 'HTTP_AUTHORIZATION' => http_auth_key }
+
+    assert_nil domains(:shop).tech_contacts.find_by(code: 'william-001')
+    assert domains(:shop).tech_contacts.find_by(code: 'john-001')
+    assert domains(:airport).tech_contacts.find_by(code: 'john-001')
+  end
+
+  def test_skip_discarded_domains
+    domains(:airport).update!(statuses: [DomainStatus::DELETE_CANDIDATE])
+
+    patch '/repp/v1/domains/contacts', { predecessor: 'william-001', successor: 'john-001' },
+          { 'HTTP_AUTHORIZATION' => http_auth_key }
+
+    assert domains(:airport).tech_contacts.find_by(code: 'william-001')
+  end
+
+  def test_return_affected_domains_in_alphabetical_order
+    patch '/repp/v1/domains/contacts', { predecessor: 'william-001', successor: 'john-001' },
+          { 'HTTP_AUTHORIZATION' => http_auth_key }
+
+    assert_response :ok
+    assert_equal ({ affected_domains: %w[airport.test shop.test],
+                    skipped_domains: [] }),
+                 JSON.parse(response.body, symbolize_names: true)
+  end
+
+  def test_return_skipped_domains_in_alphabetical_order
+    domains(:shop).update!(statuses: [DomainStatus::DELETE_CANDIDATE])
+    domains(:airport).update!(statuses: [DomainStatus::DELETE_CANDIDATE])
+
+    patch '/repp/v1/domains/contacts', { predecessor: 'william-001', successor: 'john-001' },
+          { 'HTTP_AUTHORIZATION' => http_auth_key }
+
+    assert_response :ok
+    assert_equal %w[airport.test shop.test], JSON.parse(response.body,
+                                                        symbolize_names: true)[:skipped_domains]
+  end
+
+  def test_keep_other_tech_contacts_intact
+    patch '/repp/v1/domains/contacts', { predecessor: 'william-001', successor: 'john-001' },
+          { 'HTTP_AUTHORIZATION' => http_auth_key }
+
+    assert domains(:shop).tech_contacts.find_by(code: 'acme-ltd-001')
+  end
+
+  def test_keep_admin_contacts_intact
+    patch '/repp/v1/domains/contacts', { predecessor: 'william-001', successor: 'john-001' },
+          { 'HTTP_AUTHORIZATION' => http_auth_key }
+
+    assert domains(:airport).admin_contacts.find_by(code: 'william-001')
+  end
+
+  def test_restrict_contacts_to_the_current_registrar
+    patch '/repp/v1/domains/contacts', { predecessor: 'jack-001', successor: 'william-002' },
+          { 'HTTP_AUTHORIZATION' => http_auth_key }
+
+    assert_response :bad_request
+    assert_equal ({ error: { type: 'invalid_request_error',
+                             param: 'predecessor',
+                             message: 'No such contact: jack-001' } }),
+                 JSON.parse(response.body, symbolize_names: true)
+  end
+
+  def test_non_existent_predecessor
+    patch '/repp/v1/domains/contacts', { predecessor: 'non-existent', successor: 'john-001' },
+          { 'HTTP_AUTHORIZATION' => http_auth_key }
+    assert_response :bad_request
+    assert_equal ({ error: { type: 'invalid_request_error',
+                             param: 'predecessor',
+                             message: 'No such contact: non-existent' } }),
+                 JSON.parse(response.body, symbolize_names: true)
+  end
+
+  def test_non_existent_successor
+    patch '/repp/v1/domains/contacts', { predecessor: 'william-001', successor: 'non-existent' },
+          { 'HTTP_AUTHORIZATION' => http_auth_key }
+    assert_response :bad_request
+    assert_equal ({ error: { type: 'invalid_request_error',
+                             param: 'successor',
+                             message: 'No such contact: non-existent' } }),
+                 JSON.parse(response.body, symbolize_names: true)
+  end
+
+  def test_disallow_self_replacement
+    patch '/repp/v1/domains/contacts', { predecessor: 'william-001', successor: 'william-001' },
+          { 'HTTP_AUTHORIZATION' => http_auth_key }
+    assert_response :bad_request
+    assert_equal ({ error: { type: 'invalid_request_error',
+                             message: 'Successor contact must be different from predecessor' } }),
+                 JSON.parse(response.body, symbolize_names: true)
+  end
+
+  private
+
+  def http_auth_key
+    ActionController::HttpAuthentication::Basic.encode_credentials('test_bestnames', 'testtest')
+  end
+end
diff --git a/test/integration/api/domain_transfers_test.rb b/test/integration/api/domain_transfers_test.rb
index 08ce2e34c..e70d1d272 100644
--- a/test/integration/api/domain_transfers_test.rb
+++ b/test/integration/api/domain_transfers_test.rb
@@ -53,7 +53,7 @@ class APIDomainTransfersTest < ActionDispatch::IntegrationTest
   end
 
   def test_duplicates_registrant_admin_and_tech_contacts
-    assert_difference -> { @new_registrar.contacts.size }, 2 do
+    assert_difference -> { @new_registrar.contacts.size }, 3 do
       post '/repp/v1/domain_transfers', request_params, { 'HTTP_AUTHORIZATION' => http_auth_key }
     end
   end
diff --git a/test/integration/epp/domain/transfer/request_test.rb b/test/integration/epp/domain/transfer/request_test.rb
index 508ec4334..871c3e4d6 100644
--- a/test/integration/epp/domain/transfer/request_test.rb
+++ b/test/integration/epp/domain/transfer/request_test.rb
@@ -49,7 +49,7 @@ class EppDomainTransferRequestTest < ActionDispatch::IntegrationTest
   end
 
   def test_duplicates_registrant_admin_and_tech_contacts
-    assert_difference -> { @new_registrar.contacts.size }, 2 do
+    assert_difference -> { @new_registrar.contacts.size }, 3 do
       post '/epp/command/transfer', { frame: request_xml }, { 'HTTP_COOKIE' => 'session=api_goodnames' }
     end
   end
diff --git a/test/integration/registrar/nameserver_replacement_test.rb b/test/integration/registrar/bulk_change/nameserver_test.rb
similarity index 91%
rename from test/integration/registrar/nameserver_replacement_test.rb
rename to test/integration/registrar/bulk_change/nameserver_test.rb
index 9523d2bbd..fbbdee105 100644
--- a/test/integration/registrar/nameserver_replacement_test.rb
+++ b/test/integration/registrar/bulk_change/nameserver_test.rb
@@ -1,8 +1,7 @@
 require 'test_helper'
 
-class RegistrarNameserverReplacementTest < ActionDispatch::IntegrationTest
-  def setup
-    WebMock.reset!
+class RegistrarAreaNameserverBulkChangeTest < ActionDispatch::IntegrationTest
+  setup do
     login_as users(:api_goodnames)
   end
 
@@ -21,7 +20,8 @@ class RegistrarNameserverReplacementTest < ActionDispatch::IntegrationTest
                                                }] }.to_json, status: 200)
 
     visit registrar_domains_url
-    click_link 'Replace nameserver'
+    click_link 'Bulk change'
+    click_link 'Nameserver'
 
     fill_in 'Old hostname', with: 'ns1.bestnames.test'
     fill_in 'New hostname', with: 'new-ns.bestnames.test'
@@ -40,7 +40,8 @@ class RegistrarNameserverReplacementTest < ActionDispatch::IntegrationTest
                                                            headers: { 'Content-type' => 'application/json' })
 
     visit registrar_domains_url
-    click_link 'Replace nameserver'
+    click_link 'Bulk change'
+    click_link 'Nameserver'
 
     fill_in 'Old hostname', with: 'old hostname'
     fill_in 'New hostname', with: 'new hostname'
diff --git a/test/integration/registrar/bulk_change/tech_contact_test.rb b/test/integration/registrar/bulk_change/tech_contact_test.rb
new file mode 100644
index 000000000..f45880c7b
--- /dev/null
+++ b/test/integration/registrar/bulk_change/tech_contact_test.rb
@@ -0,0 +1,47 @@
+require 'test_helper'
+
+class RegistrarAreaTechContactBulkChangeTest < ActionDispatch::IntegrationTest
+  setup do
+    login_as users(:api_bestnames)
+  end
+
+  def test_replace_domain_contacts_of_current_registrar
+    request_stub = stub_request(:patch, /domains\/contacts/)
+                     .with(body: { predecessor: 'william-001', successor: 'john-001' },
+                           basic_auth: ['test_bestnames', 'testtest'])
+                     .to_return(body: { affected_domains: %w[foo.test bar.test],
+                                        skipped_domains: %w[baz.test qux.test] }.to_json,
+                                status: 200)
+
+    visit registrar_domains_url
+    click_link 'Bulk change'
+
+    fill_in 'Predecessor', with: 'william-001'
+    fill_in 'Successor', with: 'john-001'
+    click_on 'Replace technical contacts'
+
+    assert_requested request_stub
+    assert_current_path registrar_domains_path
+    assert_text 'Technical contacts have been successfully replaced'
+    assert_text 'Affected domains: foo.test, bar.test'
+    assert_text 'Skipped domains: baz.test, qux.test'
+  end
+
+  def test_fails_gracefully
+    stub_request(:patch, /domains\/contacts/)
+      .to_return(status: 400,
+                 body: { error: { message: 'epic fail' } }.to_json,
+                 headers: { 'Content-type' => 'application/json' })
+
+    visit registrar_domains_url
+    click_link 'Bulk change'
+
+    fill_in 'Predecessor', with: 'william-001'
+    fill_in 'Successor', with: 'john-001'
+    click_on 'Replace technical contacts'
+
+    assert_text 'epic fail'
+    assert_field 'Predecessor', with: 'william-001'
+    assert_field 'Successor', with: 'john-001'
+  end
+end
diff --git a/test/integration/registrar/domain_transfers_test.rb b/test/integration/registrar/domain_transfers_test.rb
index e29a11070..59202c624 100644
--- a/test/integration/registrar/domain_transfers_test.rb
+++ b/test/integration/registrar/domain_transfers_test.rb
@@ -1,8 +1,7 @@
 require 'test_helper'
 
 class RegistrarDomainTransfersTest < ActionDispatch::IntegrationTest
-  def setup
-    WebMock.reset!
+  setup do
     login_as users(:api_goodnames)
   end
 
diff --git a/test/models/domain_transfer_test.rb b/test/models/domain_transfer_test.rb
index 7f11caf80..758a3c2ea 100644
--- a/test/models/domain_transfer_test.rb
+++ b/test/models/domain_transfer_test.rb
@@ -20,7 +20,7 @@ class DomainTransferTest < ActiveSupport::TestCase
 
     body = 'Transfer of domain shop.test has been approved.' \
       ' It was associated with registrant john-001' \
-      ' and contacts jane-001, william-001.'
+      ' and contacts acme-ltd-001, jane-001, william-001.'
     id = @domain_transfer.id
     class_name = @domain_transfer.class.name
 
diff --git a/test/models/nameserver_test.rb b/test/models/nameserver_test.rb
index 5a552a7ee..acf50eee1 100644
--- a/test/models/nameserver_test.rb
+++ b/test/models/nameserver_test.rb
@@ -50,9 +50,11 @@ class NameserverTest < ActiveSupport::TestCase
   end
 
   def test_hostnames
-    assert_equal %w[ns1.bestnames.test
+    assert_equal %w[
+      ns1.bestnames.test
       ns2.bestnames.test
       ns1.bestnames.test
+      ns2.bestnames.test
       ns1.bestnames.test], Nameserver.hostnames
   end