You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

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

ASSISTANT: Sure, I am happy to help you with that. May I know your name to check your reservation status?

USER: Sure, I am Samuel Miller.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, we have not found any active reservation on your name in our database.

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

ASSISTANT: Thank you for reaching us.