You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Anthony Lopez.

ASSISTANT: How can I guide you today?

USER: I am planning to book a direct flight for my trip, can you help me to book a flight ticket from ATL to DEN?

ASSISTANT: Sure, I will help you with that. Could you please tell me your airport codes?

USER: I have already mention my airport codes. Do you want me to provide my trip dates?

ASSISTANT: Yes, please.

USER: My planning dates are from 03/20 till 03/22.

ASSISTANT: Sorry, no flights are available on your route.

USER: No problem, thank you for checking.

ASSISTANT: Welcome, have a nice day.