If you haven't done so already, make sure you review [how to create and apply a credit memo](https://scribehow.com/shared/32_Create_and_Apply_a_Credit_Memo__89k4JzomTBG2JjAZA7b93Q), so you're familiar with the process in general.
You'll also want to familiarize yourself with [how to write off an invoice.](https://scribehow.com/shared/A49a_Writing_Off_Invoices__za_QXiLXTO-QQ_2VE158Lg)