You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: Can you book a flight ticket from DCA to PHX?

ASSISTANT: Sure, I am here to help you. May I know your travel dates please?

USER: Thank you, my planned travel dates are June, 2 and June, 4.

ASSISTANT: Ok, do you have any specifications?

USER: I need to travel in normal cost airlines and make sure that my return time should be at afternoon.

ASSISTANT: Ok, hold on for a moment. Let me check.

USER: Sure.

ASSISTANT: May I know your name please?

USER: Ryan Walker here.

ASSISTANT: Sorry Ryan Walker, there are no flights available on your requested dates.

USER: It's ok, no problem. Thank you.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.