You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Brian Williams, would it be possible to change my reservation to new travel dates?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Brian, sorry to inform you that there is no reservation found with your name in our records.

USER: It's ok, thanks for checking.

ASSISTANT: Most welcome.