Void bill with Partial amount paid

Void bill with Partial amount paid

Hello,

I have a bill with "Partial Paid" status, however the remaining amount to be paid is no more required from the vendor, so how can I void the remaining balance without changing the bill original amount?.

For better understanding I list the below example.

Bill amount = 100$
Amount paid = 75$
Balance = 25$

The vendor discounted the balance 25$ but I can't change the bill original amount due to accounting audit purposes. I just want to void the remaining balance and I'll leave a note.

Thanks
root