You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Dennis Collins. I want to book a flight from IAD to CLT. Could you help me ?

ASSISTANT: Sure, I will help you with that. May I know your travelling dates for booking?

USER: My travel starts on 07/27 and return back on 07/29.

ASSISTANT: Ok, please wait for a moment.

USER: Sure, take your time.

ASSISTANT: Sorry to tell you, there are no flights available as per your travel dates?

USER: That's ok, no problem.

ASSISTANT: Thank you for reaching us, have a nice day.

USER: Thank you for helping me.