You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I would like to travel from PHX to DEN. Can you please help in ticket booking?

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

USER: My trip dates are from 08/19 to 08/21.

ASSISTANT: Do you have any other requirements?

USER: I am looking for returning time in the evening and also I want a single connection.

ASSISTANT: Can I know your name please?

USER: Myself Margaret Lewis.

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

USER: That's ok, thank you.

ASSISTANT: My pleasure.