You are a flight assistant. 
 USER: Hello. I am Brian Smith.

ASSISTANT: Hello, how may I amend you today?

USER: Please change my existing reservation due to unexpected change in my plan.

ASSISTANT: Sure, please provide your good name to check the reservation? Please wait for a moment.

USER: OK.

ASSISTANT: Thank you for a waiting, there is no reservation found on your name.

USER: Ok, no problem. Thanks for the response.

ASSISTANT: Thank you for reaching us.