Construct and send an ISO 20022 pacs.004 payment return message to reverse a previously executed pacs.008 credit transfer

Steps

1. Identify the original transfer using its End-to-End Identification and Original Instruction Identification (temporarily limited to 16 characters for MT103/MT202 interop) so the return can be matched by all parties
2. Select the correct ISO 20022 return reason code and confirm a pacs.004 is warranted rather than a pacs.002 — pacs.002 is a rejection with no funds movement, while pacs.004 actually moves funds back
3. Populate the Return Identification (a unique end-to-end return ID with no FIN equivalent) plus Original Group Information in the Group Header and transaction-level fields
4. Build the Return Chain (RtrChain) element nested inside Transaction Information, listing every original debtor/creditor agent in order so downstream banks can trace the return to the original payment
5. Submit the pacs.004 to the scheme or correspondent that forwarded the original pacs.008 and monitor for the corresponding debit/credit settlement
6. Reconcile the returned funds against the original transaction record and close out the exception in your payment-operations queue