If the negative payable was created in hope that it would combine with an outstanding payable for the same Vendor, it will need to be reversed and a Debit Memo will have to be created.  See  FIMS Help for instructions on creating an admin Debit Memo.

To remove this negative Voucher:
  1. Go to the Open Items tab and either double-click the Voucher in the grid or select it and click the Voucher Tab. 
  2. On the bottom of the screen click the Create Debit Memo Button and enter the appropriate date. 
  3. A Debit Memo is created and can be found on the Item Entry tab. 
  4. Post the Debit Memo to remove the negative Voucher.
  5. If the Vendor credit is still valid, create a new item as a Debit Memo and post it. 
  6. This item can be applied to a new or existing Voucher to decrease the outstanding liability.