Re-lock the offer behind a fare the caller already locked with POST /v1/{vertical}/fares/build — after that fare expired for booking — and return the re-locked fare under a new fareId, the previous total, the new total, and priceChanged. The offer is the same one: same segments and fare family, same car offer, or same stay rate (room type, board, cancellation policy). Show the totals to the traveller and retry booking with the new fareId only after they confirm.\n\nIdempotency-Key is required. Replaying a key for the same fare returns the original result verbatim and does not lock a second time; a different key starts a new re-quote.