You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jack Smith.

ASSISTANT: How can I assist you?

USER: I am planning to attend meeting at Houston. Can you please help me for booking the ticket?

ASSISTANT: May I know your nearest airport codes please?

USER: I want to move from IAD to HOU.

ASSISTANT: May I know your journey dates please?

USER: I will depart on 01/05 and again I will be return back on 01/07.

ASSISTANT: Wait for a while please.

USER: Sure.

ASSISTANT: I didn't find any flights with your preferences.

USER: No problem, thank you very much for helping me.

ASSISTANT: Thank you for reaching us.