You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I am planning to change an existing reservation, due to health issue. Can you please help me out?

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

USER: My name is Nicholas Evans.

ASSISTANT: Please wait for a moment, let me check your previous reservation status.

USER: Sure.

ASSISTANT: There is no active reservation found on your name in our database to change it.

USER: That's fine, thank you for your information.

ASSISTANT: Thank you for reaching us, have a great day.