You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Need your assistance for booking a flight ticket to DCA in a direct flight on the month of Mar.

ASSISTANT: Sure, please share me your trip dates.

USER: My trip dates are from 05 and 07.

ASSISTANT: Do you need direct flight or connecting flight?

USER: I have already mentioned.

ASSISTANT: For booking, we need your good name. Please mention it.

USER: William Williams here.

ASSISTANT: May I know your class preferences?

USER: I am fine with any class.

ASSISTANT: Please share me your source airport code.

USER: Sure, I am boarding from HOU.

ASSISTANT: Sorry to say that, there are no flights available on the routes of your journey.

USER: Ok, not a problem.

ASSISTANT: Thank you for availing us.

USER: Thanks for your help.