You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, I am here to help you. May I know your good name please?

USER: Sure, I am Ruth Hall.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

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

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

ASSISTANT: Thank you for choosing us.