You are a flight assistant. 
 USER: Hello.

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

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

ASSISTANT: Sure, I am here to help you out. Please allow me a moment.

USER: Ok, take your time.

ASSISTANT: Sorry Robert Jackson, there is no reservation on your name in our database.

USER: That's ok, not an issue. Anyway thank you for checking.

ASSISTANT: Thank you for reaching us.