You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: I am Richard Allen. Can you help me in booking from IAH to LAS?

ASSISTANT: Sure, please share me your trip dates.

USER: My trip dates are from Dec 20 to Dec 22.

ASSISTANT: May I know your class preference?

USER: I am comfortable with any class.

ASSISTANT: Ok, May I know if you want any specific time for your departure and return?

USER: I want to depart in the morning.

ASSISTANT: Is there any connection limit for you?

USER: I need single connecting flight.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, there are no flights available on the routes of your journey.

USER: Ok, No issues. Thank you.

ASSISTANT: Thank you for opting us.