You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I need to give an seminar on Nano Technology in a University of New York. Please help me in booking a flight ticket.

ASSISTANT: Yes. Can you share your travel dates please?

USER: May 10 and 12 are my planned travel dates.

ASSISTANT: Now tell me your airport codes please?

USER: DEN and JFK are the respective airport codes.

ASSISTANT: May I know your name please?

USER: Jeffery Wilson here.

ASSISTANT: Do you have a connection limit?

USER: I need a direct flight.

ASSISTANT: Do you have any other preferences?

USER: I wist to depart in the afternoon.

ASSISTANT: Please wait for a moment. Thanks for your time and sorry presently direct flight is not available.

USER: That's ok. Thank you.

ASSISTANT: Thank you.