You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: Can you please help me in booking my ticket from DFW to LAX?

ASSISTANT: Sure, may I know your trip dates?

USER: My trip dates are from 07/11 to 07/13.

ASSISTANT: Do you have any other requirements?

USER: Yes, I would like to prefer business class and I also need a single connecting flight.

ASSISTANT: Ok, may I know your name please?

USER: Myself George Gonzalez.

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.