You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: Please help me to book a flight ticket from LAX to CLT.

ASSISTANT: Sure, can you share your trip dates?

USER: My trip dates are from June, 18 to June, 20.

ASSISTANT: Do you have any preferences?

USER: I need a single connecting flight and I prefer a business class.

ASSISTANT: May I know your name?

USER: I am Ruth Johnson.

ASSISTANT: Sorry, there is no flight on your given preferences.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for opting us.