You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you at this moment?

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

ASSISTANT: May I know your good name?

USER: Sure, I am Gary Lee.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: There is no reservation found on your name.

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

ASSISTANT: Thank you for choosing us.