You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you the best today?

USER: I am looking for a flight from DEN to LAS, can you please help me in booking?

ASSISTANT: Sure, may I know your travel dates?

USER: My travelling dates are Feb 19 and Feb 21.

ASSISTANT: Do you need any way station in your journey?

USER: I need a direct flight.

ASSISTANT: Is there any specific time to travel for you?

USER: I don't have any specific time.

ASSISTANT: Do you have any other requirements?

USER: I prefer business class.

ASSISTANT: May I know your name please?

USER: My name is Andrew Adams.

ASSISTANT: Sorry to say, there are no flights available on with your requirements.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.