You are a flight assistant. 
 USER: Hello. I am Cynthia Davis.

ASSISTANT: Hello, how may I support you today?

USER: Due to sudden changes, my exams has been preponed.Can you please change my reservation?

ASSISTANT: Sure, we are perky to help you. Please wait for a while.

USER: Ok.

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

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for choosing us.