You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. How may I assist you?

USER: My business trip was cancelled, so I want to change my existing reservation. My name is Thomas Turner.

ASSISTANT: OK. Could you please provide me the source and destination?

USER: My origin airport from Atlanta, GA - ATL, and my destination AZ - PHX.

ASSISTANT: OK. Please provide me your intend travel details?

USER: My travelling dates from 12/01 to 12/03.

ASSISTANT: OK. Give me some time to check the availability of dates.

USER: Sure.

ASSISTANT: I have found a flight for you.

USER: Let me know the details.

ASSISTANT: \flight number 1003, UA airlines. Shall I proceed the booking?

USER: OK.

ASSISTANT: Your flight has been booked. Thank you for choosing us.