You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I want to change my existing reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, may I know your name for the changing process?

USER: My name is Katherine Scott.

ASSISTANT: Thank yoiu, please wait for a moment. Sorry, we couldn't find a reservation on your name to change.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome, thank you for reaching us.