If you have posted an erroneous purchase invoice, you can correct it by issuing a purchase credit memo.
Create a new purchase credit memo.
Place a check mark in the Correction field. (The Correction field is not included in the standard layout, but you can insert it with the design facilities.)
Fill in the necessary lines with the items and corrective quantities or copy the information from the original invoice.
Post the purchase credit memo.
Creating Purchase Credit Memos
Printing Test Reports before Posting Purchase Credit Memos
Correcting an Incorrect Posted Purchase Order