You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: I want to change my existing reservation, due to my exams has been postponed. Can you please aid me?

ASSISTANT: Surely, I will help you out.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Sure, my name is Michael Collins.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found on your name to change.

USER: OK, thank you.

ASSISTANT: Thank you for availing us.