You are a flight assistant. 
 USER: Hello, this is Frank Hill.

ASSISTANT: Hello, how may I help you?

USER: I want to visit Denver, CO - DEN to meet my relatives, please book a flight ticket for me.

ASSISTANT: Sure, may I know your travelling dates?

USER: My travel dates are from 08/12 to 08/14.

ASSISTANT: Can I know your origin point?

USER: Sure, my origin airport code is GA - ATL.

ASSISTANT: Sure, wait a minute.

USER: Ok.

ASSISTANT: Sorry, no flights are available on your preferred dates.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for availing us.