You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I aid you today?

USER: I have a request to change an existing reservation.

ASSISTANT: OK, May I know your good name please?

USER: Brian Collins is my name.

ASSISTANT: OK, please wait for a moment I will check and get back to you.

USER: OK.

ASSISTANT: Thank you for waiting. There is no reservation found based on your name.

USER: OK, thanks for information.

ASSISTANT: Thank you for reaching us.