diff --git a/src/applications/conduit/method/differential/getcommitmessage/ConduitAPI_differential_getcommitmessage_Method.php b/src/applications/conduit/method/differential/getcommitmessage/ConduitAPI_differential_getcommitmessage_Method.php
index 2e6e045c1b..597ca7366c 100644
--- a/src/applications/conduit/method/differential/getcommitmessage/ConduitAPI_differential_getcommitmessage_Method.php
+++ b/src/applications/conduit/method/differential/getcommitmessage/ConduitAPI_differential_getcommitmessage_Method.php
@@ -25,6 +25,8 @@ class ConduitAPI_differential_getcommitmessage_Method extends ConduitAPIMethod {
   public function defineParamTypes() {
     return array(
       'revision_id' => 'required revision_id',
+      'fields' => 'optional dict<string, wild>',
+      'edit' => 'optional bool',
     );
   }
 
@@ -46,11 +48,59 @@ class ConduitAPI_differential_getcommitmessage_Method extends ConduitAPIMethod {
       throw new ConduitException('ERR_NOT_FOUND');
     }
 
-    $message_data = new DifferentialCommitMessageData(
-      $revision,
-      DifferentialCommitMessageData::MODE_AMEND);
+    $edit = $request->getValue('edit');
+    $mode = $edit
+      ? DifferentialCommitMessageData::MODE_EDIT
+      : DifferentialCommitMessageData::MODE_AMEND;
+
+    $message_data = new DifferentialCommitMessageData($revision, $mode);
     $message_data->prepare();
 
+    if ($mode == DifferentialCommitMessageData::MODE_EDIT) {
+      $fields = $request->getValue('fields');
+      if ($fields) {
+
+        static $simple_fields = array(
+          'title'           => 'Title',
+          'summary'         => 'Summary',
+          'testPlan'        => 'Test Plan',
+          'blameRevision'   => 'Blame Revision',
+          'revertPlan'      => 'Revert Plan',
+        );
+
+        foreach ($fields as $field => $value) {
+          if (isset($simple_fields[$field])) {
+            $message_data->overwriteFieldValue(
+              $simple_fields[$field],
+              $value);
+          } else {
+            $overwrite = true;
+            static $overwrite_map = array(
+              'reviewerPHIDs' => 'Reviewers',
+              'ccPHIDs' => 'CC',
+              'taskPHIDs' => 'Tasks',
+            );
+            switch ($field) {
+              case 'reviewerPHIDs':
+              case 'ccPHIDs':
+                $handles = id(new PhabricatorObjectHandleData($value))
+                  ->loadHandles($handles);
+                $value = implode(', ', mpull($handles, 'getName'));
+                break;
+              default:
+                $overwrite = false;
+                break;
+            }
+            if ($overwrite) {
+              $message_data->overwriteFieldValue(
+                $overwrite_map[$field],
+                $value);
+            }
+          }
+        }
+      }
+    }
+
     $commit_message = $message_data->getCommitMessage();
 
     return wordwrap($commit_message, 80);
diff --git a/src/applications/conduit/method/differential/getcommitmessage/__init__.php b/src/applications/conduit/method/differential/getcommitmessage/__init__.php
index d1e80a8a82..2de8f9d9d0 100644
--- a/src/applications/conduit/method/differential/getcommitmessage/__init__.php
+++ b/src/applications/conduit/method/differential/getcommitmessage/__init__.php
@@ -10,6 +10,7 @@ phutil_require_module('phabricator', 'applications/conduit/method/base');
 phutil_require_module('phabricator', 'applications/conduit/protocol/exception');
 phutil_require_module('phabricator', 'applications/differential/data/commitmessage');
 phutil_require_module('phabricator', 'applications/differential/storage/revision');
+phutil_require_module('phabricator', 'applications/phid/handle/data');
 
 phutil_require_module('phutil', 'utils');
 
diff --git a/src/applications/differential/data/commitmessage/DifferentialCommitMessageData.php b/src/applications/differential/data/commitmessage/DifferentialCommitMessageData.php
index 7e31f7e24b..9e1084ebc2 100644
--- a/src/applications/differential/data/commitmessage/DifferentialCommitMessageData.php
+++ b/src/applications/differential/data/commitmessage/DifferentialCommitMessageData.php
@@ -73,8 +73,6 @@ class DifferentialCommitMessageData {
 
     $dict['Test Plan'] = $revision->getTestPlan();
 
-    $dict['Differential Revision'] = $revision->getID();
-
     $reviewer = null;
     $commenters = array();
     $revision->loadRelationships();
@@ -145,6 +143,8 @@ class DifferentialCommitMessageData {
 
     $dict['Title'] = $revision->getTitle();
 
+    $dict['Differential Revision'] = $revision->getID();
+
     $this->dict = $dict;
   }