This type of error can affect several areas of the system (Inventory quantities for both the incorrect and the correct item, allocation, purchasing) and should be corrected as soon as possible.
Determine whether wrong item receipt caused the wrong item to be allocated to sales orders. This is a problem as the item was not actually received and therefore should not have been allocated. If the mistake did cause allocation, then any affected sales orders should be manually de-allocated from as appropriate. If any picklists were printed for the incorrectly received items, these may need to be reset before you can de-allocate the item.
Use the Inventory Adjustment program to correct the receiving error. Enter a negative quantity to reduce the quantity of the incorrect item. Charge the adjustment to the PO quantity adjustment account (this will credit the inventory and debit the PO quantity adjustment account).
Reopen the PO line (and PO header if appropriate) that was received against incorrectly so the PO line can be processed at a later time when the item is actually received.
Enter an AP invoice into the system for the value of the incorrect receipts (the invoice should be the same amount as the inventory transactions for the incorrect item). Tag the receiving transactions for the incorrect item. This invoice should have a number similar to that issued by the vendor but slightly different (like adj1) to avoid a duplicate invoice number error when the corrected transaction is processed.
Enter another AP invoice into the system for the same vendor and with a negative amount equal to that used to tag the inventory transactions in step 4. Charge the amount of the invoice to the PO quantity adjustment account (this will debit AP and credit the PO quantity adjustment account). This invoice should have a number similar to that issued by the vendor but slightly different (like adj2) to avoid a duplicate invoice number error when the corrected transaction is processed.
Apply the invoices created in the previous steps against each other using the Apply AP Credit Memo procedure. At this point.
The incorrect item is no longer in inventory
The incorrectly received against PO line is reopened
The two AP invoices entered so far offset each other and are closed so that they are not paid to the vendor.
The net effect of tagging the wrong receipts and then entering the negative invoice should cause the PO quantity account balance to be at or near 0 at end of process.
The incorrect receiving transactions are no longer showing on the unvouchered report.
Receive the correct item and process the AP invoice