You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you today?

USER: Can you help me in booking the flight ticket from IAH to LAS?

ASSISTANT: Sure, let me know your planned journey dates?

USER: My preferable journey dates are Dec 21 and Dec 23.

ASSISTANT: May I know your connection limit?

USER: I prefer connecting flight for this trip.

ASSISTANT: Is there any other preferences?

USER: I prefer to depart in afternoon flight.

ASSISTANT: Can I know your name?

USER: My name is Stephen Lee.

ASSISTANT: Thanks for your details, there is no flight found on your desired journey routes.

USER: Ok, not an issue. Thank you for providing information.

ASSISTANT: Thank you for opting us, have a nice day.