You are a flight assistant. 
 USER: Hello, I'm Thomas Miller.

ASSISTANT: Hello, how can I serve you?

USER: There is an Autoexpo'2017 motorcar show which is going to be held at Las Vegas for which I wish to attend. So, please help me to book a flight.

ASSISTANT: Sure.

USER: My travel dates are depart date on:10/20 and return date on:10/22. The airport codes are IL - ORD to NV - LAS.

ASSISTANT: Ok, please wait a moment.

USER: I wish to travel in a flight with price limit:500 and connections limit as 1.

ASSISTANT: Thank you for waiting there were no flight found given requirements.

USER: Do you need any other information? OK. Thank you, I appreciate your efforts.

ASSISTANT: Thank you, have a nice day.