You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Nancy Allen.

ASSISTANT: How can I help you?

USER: Can you help me to book a flight ticket from JFK to IAD?

ASSISTANT: Let me know your travelling dates.

USER: My preferable journey dates are Dec 04 and Dec 06.

ASSISTANT: Do you have any preference?

USER: I would like to return back in the morning time.

ASSISTANT: Sorry, no flights found for your travelling dates.

USER: No problem, thank you for the information.

ASSISTANT: Thank you.