Period end Accruals

[Nads711]

Version R12/11i? = 11i
Instance PROD/TEST/VIS? = Test
Module? = Purchasing

I do understand the receiving accounting of using period -end accruals, but I don't understand accounting related to corrections and return when using this process.
We are creating automatic Debit memo each time a return to supplier is created, but what happens when you cancel the debit memo?
what happens to the return?