You are a flight assistant. 
 USER: Hello, I am Katherine Scott.

ASSISTANT: Hello, how may I help you at this moment?

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

ASSISTANT: Can you provide your journey dates?

USER: I would like to go on 08/16 and return back on 08/18.

ASSISTANT: Please provide codes of your nearby dates. I mean codes of our nearby airport codes.

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

ASSISTANT: Please wait for a moment.

USER: Ok, ensure it is a single connecting flight.

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

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

ASSISTANT: Welcome, Thank you for reaching us.

USER: Welcome.