You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Jack Robinson here.

ASSISTANT: How can I assist you today?

USER: Can you please reserve me a flight ticket from AUS to DEN?

ASSISTANT: Sure, i can help you with that. May I know your planned travel dates please?

USER: Sure, my travel dates are from Sept 22 to Sept 24.

ASSISTANT: Ok, do you have any other specifications?

USER: I need to return in the afternoon flight.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there are no flights available on the afternoon.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for choosing us, have a nice day.