Удаление файла из множественного свойства

global $USER;
if ($USER->isAuthorized()) {
    CModule::IncludeModule('iblock');
    $file_id = htmlspecialchars($_REQUEST['file_id']);
    $check = htmlspecialchars($_REQUEST['check']);
    $user = htmlspecialchars($_REQUEST['user']);
    $iblock_id = 1;
    $result['error'] = '';
    $result['status'] = false;
    if($user == $USER->GetID()){

        $file_prop = CIBlockElement::GetProperty($iblock_id, $check, array("sort" => "asc"), array("CODE" => "IMAGES"));
        $n = 0;
        while ($file_ob = $file_prop->GetNext()) {
            if($file_ob['VALUE'] == $file_id) {
                CIBlockElement::SetPropertyValueCode($check, 'IMAGES', array($file_ob['PROPERTY_VALUE_ID'] => array('del' => 'Y')));
            }
        }

        $result['status'] = true;
    }
    echo json_encode($result);
}