You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Shirley Martin here.

ASSISTANT: How can I assist you at this moment?

USER: I want to travel from Washington to New York for attending a seminar. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, can you please provide your travelling dates?

USER: My departure date is 12/28 and return date is 12/30.

ASSISTANT: May I know your nearest airport codes of travelling?

USER: My airport codes are from IAD to JFK.

ASSISTANT: Shirley Martin, there are no flights available on this route on your requested dates.

USER: So sad for that. Anyway, thanks for the information.

ASSISTANT: Thank you for contacting us.