How to make a field editable after payment is posted

Hello colleagues

Can you please give me a hand with following topic?

We would need the ability to edit the ISR field in S4 for entity Switzerland (PBC/ISR number & ISR/QR Ref number, both fields will need to be editable after posting without having to reverse and re-enter).

Currently if we have to update this field we need to reverse invoice, clear invoice and reversal via outgoing payment app and then re-book.

The ISR Field is a standard field used to clear payment via the Swiss Banking System, if you do not enter ISR number or enter the 30 digit incorrectly the payment will be rejected

Can you please give me a hand how those field can be configured to be editable after posting?

Thank you very much for your help

Branislav