You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: Can you assist me to book flight ticket from DEN to ATL?

ASSISTANT: Sure, please share your planned trip dates?

USER: My trip dates are Dec 22 and Dec 24.

ASSISTANT: Would you like to travel in a connecting flight or a direct flight?

USER: I would like to travel in direct flight.

ASSISTANT: Do you have any particular time for departing and returning?

USER: Yes, I wish to departs in the evening and returns in the afternoon.

ASSISTANT: May I know your good name?

USER: Myself Gregory Lopez.

ASSISTANT: Sorry, there are no flights found with your given details.

USER: It's ok, thank you.

ASSISTANT: Thank you for reaching us.