In the program, return orders are usually deleted after they are invoiced. When an invoice is posted, it is transferred to the Posted Purchase Credit Memo window and, if the Return Shipment on Credit Memo check box was selected on the Purchases & Payable Setup window, the Posted Return Shipment window.
In certain situations, you may need to delete invoiced purchase return orders that were not deleted or you may need to reduce the number of posted invoices. You can delete the documents with the Delete Invd Purch. Ret. Orders batch job.
Open the 
Delete
Invd Purch. Ret. Orders batch job request form.
You can set filters on the No. (order number), Buy-from Vendor No., and Pay-to Vendor No. fields to select the orders to be deleted.
When you have set the filters, click OK to execute the batch job.
The program checks that the deleted purchase return orders have been fully invoiced. You cannot delete orders that have not been fully shipped and invoiced.
Deleting Invoiced Blanket Purchase Orders
Deleting Invoiced Purchase Orders