You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Please book a flight ticket from ORD to LAS?

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

USER: My journey dates are Jan 26 and Jan 28.

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: I prefer a return flight time at afternoon.

ASSISTANT: Can I have your name to proceed further?

USER: I am David Brown.

ASSISTANT: Ok, please wait.

USER: Sure.

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

USER: No problem, thank you for your information.

ASSISTANT: Thank you for reaching us.