You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, welcome to flight booking agency. How can I assist you today?

USER: I am Catherine Robinson. I am planning to visit Millennium Park at Chicago, could you please help me with booking a flight ticket from LAS?

ASSISTANT: Sure, can you please share your preferable travel dates?

USER: I would like to take off on 02/20 and return on 02/22.

ASSISTANT: Could you please provide the destination airport code?

USER: My destination airport code is ORD.

ASSISTANT: Ok, let me check for the availability of flight.

USER: Sure.

ASSISTANT: Catherine, I am sorry to inform you that there is no flight available at your requested dates.

USER: That's ok, I will find an another alternate way to complete my trip. Anyways, thank you for the information.

ASSISTANT: You are welcome. Thank you for contacting us.

USER: You are welcome.