Multi-turn user requests:
user: I'm considering flying in business class on November 15, 2024. What would this flight typically cost?
user: The flight is from Los Angeles International (LAX) to John F. Kennedy (JFK).
user: Once I know the cost, I need that in pounds sterling — it's easier for my budget planning. Let's base future travel expenses on the equivalent work of £10,000 using access token 'abc123xyz'.
user: Okay, I've sorted out my budget. Let's go ahead and book the flight as we discussed. Use my card — it's the one with id card_1496 — and ensure the traveler's details are correct.
user: I noticed there's a ticket linked with this booking that I no longer find necessary. Can you cancel it on my behalf?

Tools involved: TicketAPI
TravelAPI
Expected function-call sequence: TravelAPI.get_flight_cost
TravelAPI.compute_exchange_rate
TravelAPI.set_budget_limit
TravelAPI.book_flight
TicketAPI.close_ticket