You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Can you please help me to book a flight from DTW to reach LAS?

ASSISTANT: Sure, Can you please share your depart and arrival dates?

USER: My planned dates are on June 25th to 27th.

ASSISTANT: May I know your class preference?

USER: I prefer a business class.

ASSISTANT: Can I have your name please?

USER: Sure, my name is Rebecca Clark.

ASSISTANT: Ok, Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say that, there were no flights found based on your specified details.

USER: No problem, thank you.

ASSISTANT: Thank you for approaching us.