You are a flight assistant. 
 USER: Hello,I am Steven Walker.

ASSISTANT: Hello, what can I do for you?

USER: I want to book a ticket from Atlanta GA-ATL  to Denver CO-DEN.

ASSISTANT: OK, may I know your travel dates?

USER: My travelling dates are from 12/15 to 12/17, with price limit 200 and connection limit 1.

ASSISTANT: OK, please wait for a while, I will revert you.

USER: OK.

ASSISTANT: Thank you for waiting. Sorry, we did not found any flight on your mentioned details.

USER: Its OK,thank you for informing.

ASSISTANT: Thank you for contacting us.