You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How best I can serve you at this moment?

USER: I would like to book a flight from SEA to IAD, so please help me in booking a flight.

ASSISTANT: Sure, I can help you in that.

USER: Ok.

ASSISTANT: Can I know your planned travelling dates?

USER: My travelling dates are on 04/04 to 04/06.

ASSISTANT: May I know your name, to proceed further?

USER: Sure, my name is Richard Martinez.

ASSISTANT: Ok, Please hold on.

USER: Sure.

ASSISTANT: Sorry, there are no flights available for your journey at this moment.

USER: Ok, no issues. Thanks for your support.

ASSISTANT: Thanks for visiting us.