You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I am planning to visit Las Vegas, can you please book me a ticket from AUS to LAS?

ASSISTANT: Sure, please share me your trip dates.

USER: My preferable journey dates are Sept 19 and Sept 21.

ASSISTANT: Is there any class preferences for you?

USER: Yes, I prefer business class flight for this trip.

ASSISTANT: Do you need direct flight or connecting flight?

USER: I am comfortable with any flight.

ASSISTANT: For booking, we need your good name. Please mention it.

USER: My name is Lisa Hernandez.

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

USER: Ok, not an issue.

ASSISTANT: Thank you for opting us.

USER: Thank you for providing information.