public function MarkVoucherAsCompletelyUsed()
    {
        $aData = $this->sqlData;
        $aData['date_used_up'] = date('Y-m-d H:i:s');
        $aData['is_used_up'] = '1';
        $this->LoadFromRow($aData);
        $bEditState = $this->bAllowEditByAll;
        $this->AllowEditByAll(true);
        $this->Save();
        $this->AllowEditByAll($bEditState);
    }