You are a flight assistant. 
 USER: Hello, I am Dennis Turner.

ASSISTANT: Hello, how may I help you?

USER: I have planned to visit Bellagio in Las Vegas, LAS. So please help me to check a flight ticket.

ASSISTANT: Sure, can I know your current location?

USER: My current location is Atlanta and the nearby airport is ATL.

ASSISTANT: What is your trip dates?

USER: The departure date is 06/15 and the return date is 06/17.

ASSISTANT: Sorry Dennis, there is no flight for you.

USER: That's fine, thank you for searching.

ASSISTANT: It's my duty.

USER: Ok.