You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you for the day?

USER: I am Gregory Lewis. Please book a flight ticket to Denver on Oct 15th and return back on Oct 17th.

ASSISTANT: Sure, can you please help me with providing your airport codes?

USER: My journey airport codes are ATL and DEN.

ASSISTANT: Do you prefer any stopover in between journey?

USER: Yes, I prefer a stopover.

ASSISTANT: Do you prefer economy or business in your journey?

USER: I am comfortable with any class.

ASSISTANT: Is there any more specifications?

USER: I want to return in the morning.

ASSISTANT: Sorry we did not find any flights matching your preferences.

USER: Not an issue, thanks for your information.

ASSISTANT: Thank you for opting us.