If a vendor has issued a credit to your organization, create a new obligation with a negative amount.  This will be classified as a "credit memo".  The next time you print checks, include the "credit memo" obligation along with an invoice obligation and the amount of the check will be reduced by the credit amount.

When applying credit memos, you need to follow these rules:
  • You cannot apply only part of a credit memo.  Therefore, the obligations for the vendor must total more than the amount of the credit memo when you write your checks.
  • Both the credit memo and the obligation to which it is applied must be defined for combined checks.  The checkbox for 'Separate check for this obligation' cannot be marked.