undo.php

См. документацию.

<?
require($_SERVER["DOCUMENT_ROOT"]."/bitrix/modules/main/include/prolog_admin_before.php");
 
if($_SERVER["REQUEST_METHOD"] == "GET" && isset($_REQUEST['undo']) && check_bitrix_sessid())
{
    if (!CUndo::Escape($_REQUEST['undo']))
        echo 'ERROR';
}
?>