That's the easy answer. Look to the law:
(A) this paragraph and subsection (b)(3) shall not be held to preclude a licensed importer, licensed manufacturer, licensed dealer, or licensed collector from returning a firearm or replacement firearm of the same kind and type to a person from whom it was received; and this paragraph shall not be held to preclude an individual from mailing a firearm owned in compliance with Federal, State, and local law to a licensed importer, licensed manufacturer, licensed dealer, or licensed collector;
18 USC §922(A)(2)(A)
Can return to the person from whom received, says nothing about where. Even the government understands that people move. Now how the ATF wants this annotated in the bound book (if at all) and how your shipper feels about it I don't know.
