You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me to book flight ticket from DFW to ATL?

ASSISTANT: Sure, may I know your trip dates please?

USER: My trip dates are Dec 31 and Jan 2.

ASSISTANT: Do you have any other requirements?

USER: I prefer a connecting flight with business class.

ASSISTANT: Can I know your name please?

USER: Kimberly Lewis here.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: It's ok, thank you.

ASSISTANT: Most welcome.