You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Can you book a flight ticket from JFK to ATL?

ASSISTANT: Sure, may I know your travel?

USER: I will start on Dec, 17 and return on Dec, 19.

ASSISTANT: Please share me your name.

USER: Stephen Perez here.

ASSISTANT: Sorry, there is no flight at this moment.

USER: That's ok, thank you.

ASSISTANT: Thank you.