You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am looking to book a flight ticket to meet my father in Washington, can you help me for booking a flight ticket from JFK to DCA?

ASSISTANT: Sure, may I know your travel dates?

USER: My travelling dates are June 21 and June 23.

ASSISTANT: Is there any class preference for you?

USER: My preferences is business class.

ASSISTANT: Do you need a stopover?

USER: I need one stopover in my journey.

ASSISTANT: Is there any other requirements do you have?

USER: No.

ASSISTANT: May I know your good name please?

USER: My name is Andrew Moore.

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

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.

USER: Welcome.