You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

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

ASSISTANT: Sure, can you please share your journey dates?

USER: My travelling dates are Dec 9 to Dec 11.

ASSISTANT: Are you looking for any preferred connections?

USER: I need a direct flight.

ASSISTANT: Do you have any other specifications to be met?

USER: No. Kenneth Clark.

ASSISTANT: Can I have your name to proceed further? Ok, please wait.

USER: Sure.

ASSISTANT: Thank you for your valuable time, unfortunately no flights available on that route.

USER: No problem, thank you.

ASSISTANT: Thank you for opting us.