public function addUpdateMandateRequest(string $payerNr, string $newPayerNr): void
    {
        $this->mandates[] = new Record(
            'UpdateMandateRequest',
            $this->payeeBgNode,
            new Number(0, $payerNr, 'PayerNumber'),
            $this->payeeBgNode,
            new Number(0, $newPayerNr, 'PayerNumber'),
            new Text(0, str_pad('', 26))
        );
    }