You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Will you please help me in booking flight ticket from LAS to EWR?

ASSISTANT: May I know your desired travel dates please?

USER: My trip dates are Sept 13 and Sept 15.

ASSISTANT: Do you have any specifications?

USER: I need to travel in the business class which departs in the evening.

ASSISTANT: Please wait a while.

USER: Sure.

ASSISTANT: May I know your name please?

USER: Sure, I am Gary Jones.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Ok, not a problem. Thank you for checking.

ASSISTANT: Thank you for opting us.