You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am Anna Thompson, willing to travel Las Vegas.So, can you help me to book a flight ticket from Chicago, IL - ORD?

ASSISTANT: Sure, I will help you on that. Could you please provide your preferable dates that you want to travel?

USER: Sure, my preferable dates are 11/26 and 11/28.

ASSISTANT: May I know your destination airport code to proceed further?

USER: My destination airport code is NV - LAS.

ASSISTANT: Please hold on a moment to check the availability of flights and I will revert you back.

USER: Ok, sure.

ASSISTANT: Sorry to inform you, there are no flight s found with your requested dates of travelling.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for reaching us, have a great day.

USER: You are welcome.