You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I want to travel CO - DEN on 10/30 to attend an event. Can you help me to book my flight ticket?

ASSISTANT: Sure, let me know your source airport code and travel date?

USER: My source is TX - HOU. And, I want to return back from DEN to HOU on 11/01.

ASSISTANT: Can I know your name?

USER: Myself Charles Mitchell.

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

USER: Ok, it's fine.I will go with another. Thank you for the information.

ASSISTANT: You are welcome.