You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I help you today?

USER: I am Jason Phillips. Please book a flight to Denver, CO-DEN from Atlanta, GA-ATL, for shopping.

ASSISTANT: May I know your travel dates?

USER: Departure by 10/21 and return on 10/23.

ASSISTANT: Please be on hold.

USER: Sure.

ASSISTANT: Sorry to say, that there were no flights available in your preferred dates.

USER: Thanks for the help.

ASSISTANT: Thank you for reaching us.