You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Sarah Lee. I am planning to book a ticket to meet my family at BOS. Can you please help me out to book a ticket for  me?

ASSISTANT: Sure Sarah, may I know your source airport code please?

USER: My nearest source code is AZ-PHX.

ASSISTANT: Please let me know your journey dates.

USER: I would like to travel on 12/03 and return back on 12/05.

ASSISTANT: Lee, there are no flights available for you at this moment.

USER: That's fine. Thank you for your service.

ASSISTANT: Thank you for choosing us, have a good day.