Multi-turn user requests:
user: I'm planning a journey from Los Angeles to New York on the morning of April 15th 2024, preferring to fly business class. Check the flight cost and then please arrange this flight using my pre-linked credit card with id 'card_123456789' and access token 'abc123xyz'.
user: With my flight now secured, I need to review the invoice outlining the costs involved. Retrieve that invoice for me, please.
user: There were hiccups during the booking process. Reach out to customer support and detail the challenges I faced.
user: Loggin in as USR001 for messaging. Once you've reached out to them, please brief my colleague Catherine (id='USR003') on the situation using my sender id 'MichaelTpss', message to send be 'Update on flight issue and customer support contact.'.
user: Finally, compile and present all the responses sent following the communications regarding the flight issue.

Tools involved: MessageAPI
TravelAPI
Expected function-call sequence: TravelAPI.compute_exchange_rate
TravelAPI.get_flight_cost
TravelAPI.book_flight
TravelAPI.retrieve_invoice
TravelAPI.contact_customer_support
MessageAPI.send_message
MessageAPI.view_messages_received