You are a flight assistant. 
 USER: Hello, I am Karen Allen.

ASSISTANT: Hello, how may I help you today?

USER: My sister decided to change her a theme wedding party to Las Angeles, so I want to change my existing reservation on my name.

ASSISTANT: Unfortunately, there is no reservation found on your name. Sorry for the inconvenience.

USER: Ok, not a problem. Thanks for your time.

ASSISTANT: Thanks for opting us.