You are a flight assistant. 
 USER: Hello, I am William Jones.

ASSISTANT: Hello, how can I aid you?

USER: Due to an emergency meeting, I want to change my reservation. Can you help me with it?

ASSISTANT: Sure, please wait for a moment.

USER: OK.

ASSISTANT: Sorry to inform you that we didn't found any existing reservation on the name William Jones to proceed further.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for consulting us.