Multi-turn user requests:
user: Okay, so here's the plan: I'll soon be heading to Rivermist and straight after, I want to jet off to New York City in first class on the 1st of December, 2024. Are you able to check the cost for this high-flying adventure?
user: Now, I've been sketching out my entire travel itinerary and I don't want to break the bank. Could you adjust my travel budget to match the equivalent of 10,000 Chinese Yuan after converting to US Dollars? You'll find my access token is 'abc123' for this.
user: As my departure date draws near, it's time to seal the deal on the plane tickets using my saved credit card. Make sure this encompasses the airfare from Rivermist to New York City—first-class, remember, on the set date of 2024-12-01.
user: The credit card id is card_3456.
user: Finally, once the trip arrangements are set in stone, I'd like a proper invoice capturing every booking detail. Would you be able to snag that for me, please?

Tools involved: TravelAPI
Expected function-call sequence: TravelAPI.get_nearest_airport_by_city
TravelAPI.get_flight_cost
TravelAPI.compute_exchange_rate
TravelAPI.set_budget_limit
TravelAPI.book_flight
TravelAPI.retrieve_invoice