You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to book a flight ticket from PHX to MCO. Can you find a flight ticket for me?

ASSISTANT: Sure, may I know your trip dates please?

USER: Ok, my planned trip dates are on Aug 15 and return on Aug 17.

ASSISTANT: Do you have any other requirements?

USER: Ok, I want return in the afternoon time.

ASSISTANT: Can I know your name please?

USER: Ok, my name is David Brown.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: OK, not an problem.

ASSISTANT: Most welcome.