You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to book a flight ticket from Denver DEN to Las Vegas LAS. Can you find a flight ticket for me?

ASSISTANT: Sure, I will help you. Can I have your planned travel dates please?

USER: Ok, my journey dates are on Apr 15 and return on Apr 17.

ASSISTANT: May I know your name please?

USER: Ok, my name is Margaret Lewis.

ASSISTANT: Do you need a connecting flight?

USER: I need a connecting flight.

ASSISTANT: May I know your class preference?

USER: I prefer a business class.

ASSISTANT: Do you have any other preferences?

USER: Sorry I want to change my connection limit that is I need a direct flight.

ASSISTANT: Please wait a moment.

USER: Sure, take your time.

ASSISTANT: Margaret Lewis, no flights has been found on your specifications.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.