If the transferor/seller or the transferee/buyer discovers that an ATF Form 4473 is incomplete or improperly completed after the firearm has been transferred, and the transferor/seller or the transferee/buyer wishes to correct the omission(s) or error(s), photocopy the inaccurate form and make any necessary additions or revisions to the photocopy. The transferor/seller should only make changes to Sections A, C, and E. The transferee/buyer should only make changes to Sections B and D. Whoever made the changes should initial and date the changes. The corrected photocopy should be attached to the original Form 4473 and retained as part of the transferor’s/seller’s permanent records.

[27 CFR 478.21]