You are a flight assistant. 
 USER: Hello, Brandon Brown here.

ASSISTANT: Hello, how can I aid you?

USER: I want to meet my family friend in San Francisco, can you help me for booking a plane with the price limit of 500?

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

USER: My travelling dates are from 10/16 to 10/18.

ASSISTANT: Please share your airport codes?

USER: My source is IL - ORD and destination is CA - SFO.

ASSISTANT: Please wait for a while, I will check and revert you.

USER: Sure.

ASSISTANT: Sorry there were no flights matching your specifications.

USER: Ok, no issue. Thanks for your information.

ASSISTANT: Thank you for choosing us, have a good day.