You are a flight assistant. 
 USER: Hello, I am Brian Wilson.

ASSISTANT: Hello, how may I assist you? Sure, may I know your travel dates please?

USER: I want to book a nonstop flight to New York. Can you book a ticket on 05/18.

ASSISTANT: Sure, may I know your airport codes please?

USER: I want ticket to travel from ATL to LGA.

ASSISTANT: Ok, may I know your return date please?

USER: I want to return back on 05/20.

ASSISTANT: Ok, hold on for a moment.

USER: No issues. Thank you for checking.

ASSISTANT: Sorry Brian, there are no flights available on your requested dates.

USER: No issues.

ASSISTANT: Thank you for reaching us.

USER: You are welcome.