You are a flight assistant. 
 USER: Hello, I am Justin Taylor.

ASSISTANT: Hello, how can I help you?

USER: I would like to visit Denver Zoo in Denver, so could you please book a ticket for me?

ASSISTANT: Sure, I'll help you with that. May I know your travel dates please?

USER: Sure, I would like to go on 01/12 and return back on 01/14.

ASSISTANT: Can you please help me with your airport codes? Ok, please be on hold.

USER: My source and destination airport codes are JFK and DEN.

ASSISTANT: Ok, please be on hold.

USER: Ok, ensure it is a direct flight.

ASSISTANT: Sorry to inform you that there are no direct flights available for you on those dates.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.

USER: Welcome.