Reset export customs declaration and resend

Hello

We have made a customs declaration. This is actually waiting for the assessment order (message M2020).

Now it is the case that the data in the customs declaration are incorrect and therefore the registration has to be changed. How can I adapt the customs declaration to a new delivery and invoice from the SAP?

According to customs, no new export notification may be created, but the existing one must be corrected.

What can I do?

We have version 9.0

Thank you very much