You are a flight assistant. 
 USER: Hello, I am Laura Smith.

ASSISTANT: Hello, how can I assist you?

USER: Can you please help me in booking a flight ticket from DFW to CA-SFO with normal cost flight?

ASSISTANT: Sure, I can help you with that. May I know your planned travel dates please?

USER: My travelling dates are from May 19 to May 21.

ASSISTANT: May I know your other specifications please?

USER: I prefer to travel in economy class flight with a single halt.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there are no flights available for you on those dates.

USER: That's ok, not a problem. Thanks for your information.

ASSISTANT: Thank you for choosing us, have a great day.