You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Robert Edwards. I am planning to visit Arizona State Capitol it is in Phoenix on 07/17, can you please help me in booking flight ticket?

ASSISTANT: Sure. Let me know your travelling location codes?

USER: My origin airport code is DEN and destination airport code is PHX.

ASSISTANT: Do you have planned for a return date?

USER: I want return to DEN on 07/19.

ASSISTANT: Thank you for your information. Sorry, there is no flight available for your dates.

USER: Oh it's ok, no problem. Thank you for your service.

ASSISTANT: Welcome.