You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am William Collins.

ASSISTANT: How may I aid you?

USER: I planned to meet my cousin in SFO, can you please help me to book a flight ticket from DFW?

ASSISTANT: Sure, I am here to help you. Can you please share your travel dates?

USER: I prefer to travel on Jan 19 and Jan 21.

ASSISTANT: Do you have any connection limit?

USER: I prefer to travel in a connecting flight.

ASSISTANT: May I know your airline preference?

USER: I am comfortable with any airline.

ASSISTANT: Which class do you prefer?

USER: I am comfortable with any class.

ASSISTANT: Do you have any specific departure and arrival time?

USER: I would like to return back in morning.

ASSISTANT: Ok, please be on hold.

USER: Sure.

ASSISTANT: Sorry, there are no flights in this route as per your travelling details.

USER: Ok, no problem. Thank you for your time.

ASSISTANT: Thank you for reaching us.