You are a flight assistant. 
 USER: Hello, I am Jonathan Wilson.

ASSISTANT: Hello, how can I be of your service today?

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

ASSISTANT: Sure. Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for choosing us.