diff --git a/.github/workflows/automerge-sync-pr.yml b/.github/workflows/automerge-sync-pr.yml
index c9490e2..4b996c2 100644
--- a/.github/workflows/automerge-sync-pr.yml
+++ b/.github/workflows/automerge-sync-pr.yml
@@ -1,12 +1,12 @@
 name: Auto merge changes made to the target branches in a pull request
 
 on:
-  pull_request:
-    types:
-      - opened
-    branches:
-      - unstable
-      - experiment
+  workflow_dispatch:
+    inputs:
+      pr_number:
+        description: Pull request number
+        required: true
+        type: string
 
 jobs:
   sync-changes:
@@ -14,14 +14,6 @@ jobs:
     permissions:
       contents: write
       pull-requests: write
-    strategy:
-      matrix:
-        include:
-          - branch: unstable
-            labels: branch/unstable
-          - branch: experiment
-            labels: branch/experiment
-      fail-fast: false
     steps:
       - name: Generate GitHub Auth Token
         # https://github.com/tibdex/github-app-token
@@ -37,12 +29,13 @@ jobs:
         uses: pascalgn/automerge-action@main
         env:
           GITHUB_TOKEN: ${{ steps.generate_token.outputs.token }}
-          MERGE_LABELS: "automerge"
-          MERGE_REMOVE_LABELS: "automerge"
-          MERGE_METHOD: "squash"
-          MERGE_COMMIT_MESSAGE: "ci(github-action): auto merge {pullRequest.number}"
-          MERGE_FORKS: "false"
-          MERGE_RETRIES: "0"
-          MERGE_RETRY_SLEEP: "0"
-          MERGE_REQUIRED_APPROVALS: "0"
+          MERGE_LABELS: automerge
+          MERGE_REMOVE_LABELS: automerge
+          MERGE_METHOD: squash
+          MERGE_COMMIT_MESSAGE: "ci(github-action): auto merge ${{ inputs.pr_number }}"
+          MERGE_FORKS: false
+          MERGE_RETRIES: 0
+          MERGE_RETRY_SLEEP: 0
+          MERGE_REQUIRED_APPROVALS: 0
           BASE_BRANCHES: "unstable,experiment"
+          PULL_REQUEST: ${{ inputs.pr_number }}
diff --git a/.github/workflows/sync-changes-to-child-branches.yml b/.github/workflows/sync-changes-to-child-branches.yml
index 99ffdc5..69827df 100644
--- a/.github/workflows/sync-changes-to-child-branches.yml
+++ b/.github/workflows/sync-changes-to-child-branches.yml
@@ -26,7 +26,9 @@ jobs:
               branch/unstable
               automerge
           - branch: experiment
-            labels: branch/experiment
+            labels: |
+              branch/experiment
+              automerge
       fail-fast: false
     steps:
       - name: Generate GitHub Auth Token
@@ -54,6 +56,7 @@ jobs:
       - name: Cherry pick changes into target branch
         # https://github.com/carloscastrojumo/github-cherry-pick-action
         uses: carloscastrojumo/github-cherry-pick-action@main
+        id: cherrypick_pr
         with:
           branch: ${{ matrix.branch }}
           labels: |
@@ -65,3 +68,16 @@ jobs:
           cherry-pick-branch: cherrypick-${{ env.COMMIT_SHORT_SHA }}-${{ matrix.branch }}
         env:
           GITHUB_TOKEN: ${{ steps.generate_token.outputs.token }}
+
+      - name: Trigger downstream workflow
+        uses: convictional/trigger-workflow-and-wait@v1.6.5
+        with:
+          owner: ${{ github.repository_owner }}
+          repo: flake.nix
+          github_token: ${{ steps.generate_token.outputs.token }}
+          workflow_file_name: automerge-sync-pr.yml
+          ref: ${{ github.event.repository.default_branch }}
+          client_payload: '{"pr_number":"${{ steps.cherrypick_pr.outputs.number }}"}'
+          trigger_workflow: true
+          propagate_failure: false
+          wait_workflow: false