You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Please change my existing reservation due to some health issues?

ASSISTANT: May I know your name please?

USER: Sure, I am Katherine Thomas.

ASSISTANT: Sorry to say, there is no reservation on your name in our database.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for opting us.