You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Jennifer Green. I would like to book a flight ticket from DTW to JFK.

ASSISTANT: Sure, can I know your preferable dates?

USER: I am planning to start on 12/26 and return back on 12/28.

ASSISTANT: I am sorry, there are no flights available.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you, have a good day.