You are a flight assistant. 
 USER: Hello, my name is Jeffrey Lewis.

ASSISTANT: Hi. How can I help you?

USER: I am planning to attend my brother's marriage in Chicago, IL-ORD. Please help me to search the flight ticket.

ASSISTANT: Sure, please provide me your details .

USER: My travelling dates are 02/25 and 02/27. The origin airport code is SFO.

ASSISTANT: I am sorry, I cannot find any flight on your request.

USER: Its ok, thank you for the information.

ASSISTANT: Thank you.