You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to book a flight ticket from SFO to PHL. Could you help me in booking?

ASSISTANT: May I know your desired travel dates please?

USER: My travelling dates are from Dec 11-13.

ASSISTANT: May I know your name please?

USER: Stephanie Baker here.

ASSISTANT: Do you have any specification?

USER: I need direct flight.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: That's ok, no problem.

ASSISTANT: Thank you for opting us.

USER: Thank you.