diff --git a/types/office-js/index.d.ts b/types/office-js/index.d.ts
index 105062a56e..26631c8c1d 100644
--- a/types/office-js/index.d.ts
+++ b/types/office-js/index.d.ts
@@ -1035,6 +1035,10 @@ declare namespace Office {
         *     <td>12007</td>
         *     <td>A dialog box is already opened from the task pane. A task pane add-in can only have one dialog box open at a time.</td>
         *   </tr>
+        *   <tr>
+        *     <td>12009</td>
+        *     <td>The user chose to ignore the dialog box. This error can occur in online versions of Office, where users may choose not to allow an add-in to present a dialog.</td>
+        *   </tr>
         * </table>
         * 
         * In the callback function passed to the displayDialogAsync method, you can use the properties of the AsyncResult object to return the