You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: I am Charles Wright. I would like to book a flight ticket from PHX to IAH.

ASSISTANT: Sure, can I know your preferable dates?

USER: I am starting on 07/06 and return back on 07/08.

ASSISTANT: I am sorry, there are no flights available. Thank you, have a good day.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you, have a good day.