You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Please change my existing reservation due to my meeting postponed a week.

ASSISTANT: Ok, may I know your name please?

USER: Kimberly Campbell is my name.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say that, there was no reservation found with your name to change.

USER: Ok, no problem.

ASSISTANT: Thank you for opting us.