Multi-turn user requests:
user: I'd love a comprehensive list of all available departure airports to commence my travel planning, please share what's accessible.
user: As I map out my journey, I require the specific details of the nearest airport from charming Rivermist for my departure.
user: Great! To proceed, I'd like to ascertain the estimated airfare from tranquil Rivermist to the dynamic New York City, considering an economy ticket for this Sunday 09/10, 2024.
user: Subsequent to determining the air ticket cost, I need to convert the expense into RMS and establish it as my fiscal threshold. Could you assist with that exchange rate adjustment and budget setting using access token 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9' to 2940?
user: I'm ready to proceed with booking the flight. Kindly utilize my access credentials to finalize the reservation, charging it to the credit card registered with id 'card6749', using my traveler particulars.
user: A minor matter needs addressing: my departure date had an open query. Could you close ticket number 458219 for me?

Ground-truth function call sequence:
TravelAPI.list_all_airports
TravelAPI.get_nearest_airport_by_city
TravelAPI.get_flight_cost
TravelAPI.compute_exchange_rate
TravelAPI.set_budget_limit
TravelAPI.book_flight
TicketAPI.close_ticket