You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be your guide for today?

USER: My name is Barbara Nelson. I already book a flight to St.Paul with business class, can you change my reservation to economy class?

ASSISTANT: Sure, I am here to help you about that Barbara Nelson.

USER: Thank you.

ASSISTANT: Please let me check the reservation status with your name in our booking list.

USER: Sure, I will wait for your reply.

ASSISTANT: Sorry to say this Barbara Nelson, there is no active reservation with your name in our booking list to change your reservation.

USER: Ok, thank you for the information.

ASSISTANT: You are welcome, thank you for choosing our service. Hope you have a nice day ahead.