You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Ronald Williams, I want to change my reservation as I changed my plan to visit my sister.

ASSISTANT: Sure. Please wait for a while.

USER: Sure.

ASSISTANT: We have not found any flight reservation on your given name.

USER: Thank you helping me.

ASSISTANT: Thanks for choosing us.