You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Catherine Wright here, I want to alter my reservation, due to postponement of concert to be held at the place where I wanted to visit. Can you please change my existing reservation?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found with your name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Ok, thank you for choosing us.