You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Can you please help me to change my existing reservation, due to my trip has been postponed?

ASSISTANT: Sure, I am here to help you out. Please provide me your name to check the reservation status.

USER: Sure, please check my reservation on the name of Lisa Scott.

ASSISTANT: Please allow me a moment.

USER: Sure.

ASSISTANT: Sorry Lisa Scott, there is no flight reservation on your name.

USER: Ok, thanks for your service.

ASSISTANT: Thank you for reaching us Lisa Scott.