Purchase Return or Debit Note

A debit note is issued when there is a purchase return and reduces receivables, while a credit note is issued when there is a sales return and reduces payables. 

When the buyer records a purchase return, it can be either as a credit to its inventory account (if there are few such transactions) or to a purchase returns account (if management wants to segregate this information for further analysis). The offsetting debit is to the accounts payable account.