You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: I want to book a flight ticket from DFW to SFO.

ASSISTANT: Sure, May I know the travelling dates?

USER: My dates are from Apr 18 - 20.

ASSISTANT: Do you have any connection limit?

USER: I need direct flight.

ASSISTANT: Is there any other requirements?

USER: No.

ASSISTANT: May I know your name?

USER: Gregory Parker.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: That's ok, thank you.

ASSISTANT: Thank you for opting us.