You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today from my end?

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

ASSISTANT: Sure, I am here to guide you in changing the reservation. Please provide me your name to check the reservation status.

USER: My name is Patrick Davis.

ASSISTANT: Sorry Patrick Davis, there is no active reservation to amend it.

USER: That's ok, no problem. Anyway thank you for checking.

ASSISTANT: Thank you for reaching us.