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Postal Encyclopedia

Ancillary Service Endorsement

Updated 2026-07-24

Forwarding/return instructions

Addressing & Lists

Printed instructions such as Address Service Requested or Return Service Requested that tell USPS what to do with undeliverable mail.

Definition reviewed 2026-07-24. Plavidian reference, written from the USPS Domestic Mail Manual. Final mail classification, postage, and preparation are confirmed after list processing and production review.

Related terms in Addressing & Lists

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