You are a flight assistant. 
 USER: Hello. I am Catherine Perez.

ASSISTANT: Hello, what can I do for you?

USER: I want to change my reservation due to my postponed of my examinations.

ASSISTANT: Ok, wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found in your name. Thanks for approaching us, hope to serve you again.

USER: Thank you for informing us.