You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: Can you help me to book a flight ticket from SFO to DFW?

ASSISTANT: May I know your trip dates?

USER: My travel dates are Sept 15 and Sept 17.

ASSISTANT: Can I know your connection limit?

USER: I prefer connecting flight for this trip.

ASSISTANT: Please let me know do you have any other requirements?

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

ASSISTANT: May I know your name please?

USER: I am Nancy Johnson.

ASSISTANT: sorry, no flights available on your route.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.