You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may we assist you today?

USER: I am Michael Green.

ASSISTANT: OK.

USER: I would like to attend a seminar on Online Trading in John Hancock Center at Chicago, ORD.

ASSISTANT: OK.

USER: Can you please make a reservation from Las Vegas, LAS?

ASSISTANT: Sure, to search a flight for you I need your travel dates?

USER: My journey dates are, departure on 03/11 and and arrival on 03/1. Arrival on 03/13.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting. Sorry, no flights are available on your preferred dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thanks for approaching us, have a great day.