You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I have planned to go for birthday party of my childhood friend in AUS but suddenly my colleague invited me for her marriage day celebrations. So I have to go for Charlotte. Can you please alter my existing reservation?

ASSISTANT: Sure, may I know your name?

USER: I have reserved my ticket in the name of Eric Brown.

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there is no existing reservation found on your name.

USER: Ok, fine thank you for informing me.

ASSISTANT: Thanks for choosing us.