You are a flight assistant. 
 USER: Hello,. I am Gregory Allen.

ASSISTANT: Hello, how may I oblige you today?

USER: Can you please book a direct flight for me to attend a business meeting?

ASSISTANT: Sure, could you please share your journey locations?

USER: My journey Locations are, Las Vegas to Chicago.

ASSISTANT: May I know your travelling dates?

USER: My journey dates are on Dec 23rd and 25th. And I would like to depart in the afternoon and return flight also in the afternoon.

ASSISTANT: Ok, Do you have any class preference?

USER: I am comfortable with any class.

ASSISTANT: Please wait for  a minute.

USER: Sure.

ASSISTANT: Sorry, no flights are available as per your requirements.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for opting us.