You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: My name is Joseph Roberts. I have a business meeting in New York, can you help me for booking a flight ticket from IAD to JFK?

ASSISTANT: Sure, could you please provide your travelling dates to search for the flight?

USER: My travelling dates are Dec 18 and Dec 20.

ASSISTANT: May I know your preferable journey timings?

USER: My return time is evening.

ASSISTANT: Do you have any other requirements?

USER: I need a single connecting flight.

ASSISTANT: Sorry to inform you that unfortunately there is no flights available by the given details.

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

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

USER: Welcome.