diff --git a/app/controllers/downtimes_controller.rb b/app/controllers/downtimes_controller.rb
index 99b8b27c0..e828cc646 100644
--- a/app/controllers/downtimes_controller.rb
+++ b/app/controllers/downtimes_controller.rb
@@ -1,7 +1,7 @@
 class DowntimesController < ApplicationController
   before_action :require_govuk_editor
   before_action :load_edition
-  before_action :process_params, only: %i[create]
+  before_action :process_params, only: %i[create update]
 
   def new
     @downtime = Downtime.new(artefact: @edition.artefact)
@@ -18,6 +18,26 @@ def create
     end
   end
 
+  def edit
+    @downtime = Downtime.for(@edition.artefact)
+  end
+
+  def update
+    @downtime = Downtime.for(@edition.artefact)
+
+    if params["commit"] == "Cancel downtime"
+      DowntimeRemover.destroy_immediately(@downtime)
+      flash[:success] = "#{edition_link} downtime message cancelled".html_safe
+      redirect_to downtimes_path
+    elsif @downtime.update(downtime_params)
+      DowntimeScheduler.schedule_publish_and_expiry(@downtime)
+      flash[:success] = "#{edition_link} downtime message re-scheduled (from #{view_context.downtime_datetime(@downtime)})".html_safe
+      redirect_to downtimes_path
+    else
+      render :edit
+    end
+  end
+
 private
 
   def downtime_params
diff --git a/app/views/downtimes/edit.html.erb b/app/views/downtimes/edit.html.erb
new file mode 100644
index 000000000..9d263c669
--- /dev/null
+++ b/app/views/downtimes/edit.html.erb
@@ -0,0 +1,19 @@
+<% content_for :page_title, 'Re-schedule downtime message' %>
+
+<ul class="breadcrumb">
+  <li class="crumb"><%= link_to 'Downtime', downtimes_path %></li>
+  <li class="active"><%= @downtime.artefact.name %></li>
+</ul>
+
+<div class="page-title">
+  <h1>
+    <span class="small"><%= @downtime.artefact.name %></span>
+    Re-schedule downtime message
+  </h1>
+</div>
+
+<%= form_for @downtime, url: edition_downtime_path(@edition), html: { class: 'form well remove-top-margin', 'data-module': 'downtime-message' } do |f| %>
+  <%= render 'form', f: f %>
+  <%= f.submit 'Re-schedule downtime message', class: 'js-submit btn btn-success' %>
+  <%= f.submit 'Cancel downtime', class: 'add-left-margin btn btn-danger' %>
+<% end %>
diff --git a/config/features.rb b/config/features.rb
index 52fc88a34..6976dc26e 100644
--- a/config/features.rb
+++ b/config/features.rb
@@ -16,4 +16,8 @@
   feature :design_system_downtime_new,
           default: false,
           description: "A transition of the add downtime page to use the GOV.UK Design System"
+
+  feature :design_system_downtime_edit,
+          default: false,
+          description: "A transition of the edit downtime page to the GOV.UK Design System"
 end
diff --git a/config/routes.rb b/config/routes.rb
index e7dd1626f..7f51b36b1 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -45,6 +45,9 @@
     constraints FeatureConstraint.new("design_system_downtime_new") do
       resource :downtime, only: %i[new create]
     end
+    constraints FeatureConstraint.new("design_system_downtime_edit") do
+      resource :downtime, only: %i[edit update]
+    end
     resource :downtime, only: %i[new create edit update destroy], controller: "legacy_downtimes"
   end
 
diff --git a/test/functional/downtimes_controller_test.rb b/test/functional/downtimes_controller_test.rb
index 745d5459d..d3c9dc571 100644
--- a/test/functional/downtimes_controller_test.rb
+++ b/test/functional/downtimes_controller_test.rb
@@ -50,6 +50,51 @@ class DowntimesControllerTest < ActionController::TestCase
     end
   end
 
+  context "#edit" do
+    should "render the page ok" do
+      create_downtime
+      get :edit, params: { edition_id: edition.id }
+      assert_response :ok
+    end
+  end
+
+  context "#update" do
+    context "cancelling scheduled downtime" do
+      should "invoke the DowntimeRemover" do
+        DowntimeRemover.expects(:destroy_immediately).with(downtime)
+        put :update, params: { edition_id: edition.id, downtime: downtime_params, commit: "Cancel downtime" }
+      end
+
+      should "redirect to the downtime index" do
+        DowntimeRemover.stubs(:destroy_immediately)
+        put :update, params: { edition_id: edition.id, downtime: downtime_params, commit: "Cancel downtime" }
+        assert_redirected_to controller: "legacy_downtimes", action: "index"
+      end
+    end
+
+    context "rescheduling planned downtime" do
+      should "schedule the changes for publication and expiration" do
+        DowntimeScheduler.expects(:schedule_publish_and_expiry).with(downtime)
+        put :update, params: { edition_id: edition.id, downtime: downtime_params, commit: "Re-schedule downtime message" }
+      end
+
+      should "redirect to the downtime index" do
+        create_downtime
+        DowntimeScheduler.stubs(:schedule_publish_and_expiry)
+        put :update, params: { edition_id: edition.id, downtime: downtime_params, commit: "Re-schedule downtime message" }
+        assert_redirected_to controller: "legacy_downtimes", action: "index"
+      end
+    end
+
+    context "with invalid form data" do
+      should "rerender the page" do
+        create_downtime
+        put :update, params: { edition_id: edition.id, downtime: invalid_params, commit: "Re-schedule downtime message" }
+        assert_template :edit
+      end
+    end
+  end
+
   def edition
     @edition ||= FactoryBot.create(:transaction_edition)
   end
diff --git a/test/integration/routes_test.rb b/test/integration/routes_test.rb
index 984213dfe..481f0e1c6 100644
--- a/test/integration/routes_test.rb
+++ b/test/integration/routes_test.rb
@@ -14,4 +14,13 @@ class RoutesTest < ActionDispatch::IntegrationTest
 
     assert_routing("/reports", controller: "legacy_reports", action: "index")
   end
+
+  should "route to legacy reports controller when 'design_system_downtime_edit' toggle is enabled" do
+    test_strategy = Flipflop::FeatureSet.current.test!
+    test_strategy.switch!(:design_system_downtime_edit, true)
+    edition = FactoryBot.create(:edition)
+    edition_id = edition.id.to_s
+
+    assert_routing("/editions/#{edition_id}/downtime/edit", controller: "downtimes", action: "edit", edition_id:)
+  end
 end