How to write off an underpayment

Hi,

One of my clients refused to pay the full invoice due. I threatened her with the small claims court, but, to cut a long story short, my legal advisor recommended negotiating with the client. The upshot is that she has agreed to pay, and I have agreed to accept a lower figure, based on an estimate I gave her before the work started. How do I write off the difference between the original invoice and the lower figure we’ve agreed?

Thanks in advance.

You can just issue a credit note for the difference