You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: I want to change my reservation due to postponed of my exam, so please help me.

ASSISTANT: Sure, I am gleeful to help you with that. May I know your name please?

USER: Sure, my name is Elizabeth Martin.

ASSISTANT: Please wait for a moment, let me check your previous reservation status.

USER: Sure.

ASSISTANT: Thank you for waiting. There is no active reservation found on your name in our database to change it.

USER: Not a problem, thank you.

ASSISTANT: Thank you for reaching us, have a great day.