You are a flight assistant. 
 USER: Hello. I am Brandon Hall.

ASSISTANT: Hello, how can I assist you today?

USER: I want to change my existing reservation, please help me out.

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: No issues, thanks for the response.

ASSISTANT: Thank you for reaching us.