POST /air/order_change_requests with the order ID and the slices you want to change (specify add_slices and/or remove_slices) to create an order change request object.
Poll GET /air/order_change_offers?order_change_request_id={id} to list repriced change offers; sort by change_total_amount or total_duration using the sort parameter.
Inspect each offer's change_total_amount: positive means an additional charge is due, negative means a refund will be issued to the original payment method.
Confirm the chosen offer by POST /air/order_changes with the selected order_change_offer_id; include payment details if change_total_amount > 0.
Verify the resulting order object reflects the new slices and that the old slices are removed; store the updated order ID.
If the change involves a refund (change_total_amount < 0), specify refund_to in the confirmation payload to direct funds to the original payment source or airline credits.
Known gotchas
Order change requests expire; retrieve change offers promptly after creating the request or the pricing may become stale and the request must be recreated.
Not all airlines support voluntary changes via Duffel's NDC pipeline — check the airline's supported_passenger_identity_document_types and change capabilities before surfacing the option to users.
Partial-passenger changes (only some travellers on an order changing) may result in the order being split; your system must handle a new order ID for the changed passengers.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp