Index: plugins/user_relationship_invites/user_relationship_invites.module
===================================================================
--- plugins/user_relationship_invites/user_relationship_invites.module	(.../orig/current/sites/all/modules/user_relationships)	(revision 3357)
+++ plugins/user_relationship_invites/user_relationship_invites.module	(.../trunk/sites/all/modules/user_relationships)	(revision 3357)
@@ -95,6 +95,9 @@
      $args['inviter']->uid, $form_values['rtid'], $args['code']
    );
     break;
+  case 'cancel':
+    db_query("DELETE FROM {user_relationship_invites} WHERE invite_code = '%s'", $args['code']);
+    break;
   }
 }