You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I am Mary Jackson, want to travel from LGA to ATL. Please help me in booking my ticket.

ASSISTANT: Sure, I am glad to help you in booking the flight ticket. May I know your planned travel dates?

USER: Sure, my travelling dates are from 12/15 to 12/17.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting.

USER: Ok.

ASSISTANT: Sorry to say, there are no flights available for your desired dates.

USER: It's ok, thank you for your help.

ASSISTANT: Thank you for opting us.