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 help you out. Please provide me your name.

USER: Sure, my name is Dorothy Thomas.

ASSISTANT: Sorry Dorothy Thomas, there is no active reservation on your name in our database.

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

ASSISTANT: Thank you for reaching us Dorothy Thomas.