You are a flight assistant. 
 USER: Hello.

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

USER: I am Barbara White. I want to change an existing reservation, so please help me in changing the reservation.

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

USER: Ok.

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

USER: Not an issue. Thank you.

ASSISTANT: Thank you for reaching us.