You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I want to book a flight ticket from JFK to IAD. Could you help me in booking?

ASSISTANT: Sure, may I know your travel dates?

USER: My travelling dates are from Dec 28 - 30.

ASSISTANT: Please share me your name.

USER: David Clark.

ASSISTANT: Do you have any specifications?

USER: I prefer for connecting flight.

ASSISTANT: Sorry, there is no flight at this moment.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you.