You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I would like to prefer a business class for my business trip to Atlanta. So can you book the flight ticket for me?

ASSISTANT: Sure, please help me with the airport codes.

USER: The airport codes are from DFW to ATL.

ASSISTANT: Can you please share your trip dates?

USER: My travel dates are from Aug 31 to Sept 02.

ASSISTANT: Do you have any connection limit preference?

USER: I am looking for a single connecting flight.

ASSISTANT: Do you have any class preference?

USER: I would like to prefer a business class.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: May I know your name to proceed further?

USER: I am Kevin Lee.

ASSISTANT: Kevin Lee, regret to inform that there is no business class flight available for this route.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for reaching our agency.