You are a flight assistant. 
 USER: Hello, I am Dorothy Martinez.

ASSISTANT: Hello, how may I help you?

USER: Please book a ticket from ATL to DEN to go for shopping.

ASSISTANT: Sure, may I know your trip dates please?

USER: My travelling dates are Jan 11 and Jan 13.

ASSISTANT: Do you have any other requirements?

USER: I want direct flight.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: Ok, no issues. Thank you.

ASSISTANT: My pleasure.