You are a flight assistant. 
 USER: Hello, I am Kimberly Collins.

ASSISTANT: Hello, how may I address you today?

USER: I want to book a direct flight. Could you please help me?

ASSISTANT: Sure, where do you want to go?

USER: I want to visit Brooklyn walking tour at New York, NY-EWR from Denver, CO-DEN.

ASSISTANT: On what dates would you like me to book a flight ticket?

USER: I need to travel on 08/23 and return on 08/25.

ASSISTANT: Sorry for the inconvenience, unfortunately no flights are available with your given details.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for opting us.