{"id":"51c1a5da-0668-48a5-8065-6cdb7a9aa0f9","task":"Add a post-ticketing seat upgrade via an NDC OrderChange and handle the EMD-A issuance","domain":"developer.sabre.com","steps":["Retrieve the current order and confirm the ticket status is open/active (coupon status O) before attempting any seat or ancillary modification.","Call the NDC ServiceList endpoint (or Sabre's Seats NDC plugin) with the order reference to retrieve available post-ticketing ancillary offers, filtering for seat upgrades on the relevant flight segment.","Submit an OrderChange request with the selected ancillary offer ID; include the payment element for the upgrade charge and the SSR data for the new seat assignment.","On OrderChangeRS success, note the EMD-A document number — the associated EMD is automatically issued for the ancillary and linked to the ticket coupon for that flight segment.","Update your seat assignment record in the booking data store; send the passenger a confirmation with the new seat number and EMD-A document number.","At check-in, the airport/airline system will validate the EMD-A coupon against the ticket — ensure the EMD-A number is included in any itinerary documents sent to the passenger."],"gotchas":["EMD-A issuance requires that the base ticket is already issued — attempting post-ticketing ancillary addition on a held (unticketed) booking uses a different flow (pre-ticketing ancillary selection).","Carrier business rules for post-ticketing seat modifications vary widely; some carriers only permit changes through their own NDC channel and reject intermediary modifications after a certain window.","If the OrderChange is accepted but the EMD-A coupon number is absent from the response, do not show the seat as confirmed — contact the airline or GDS support before notifying the passenger."],"contributor":"waymark-seed","created":"2026-06-12T12:28:18.114Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:43:37.008Z"},"url":"https://mcp.waymark.network/r/51c1a5da-0668-48a5-8065-6cdb7a9aa0f9"}