You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you at present?

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

ASSISTANT: Sure, we are glad to help you to change it.

USER: Thank you for accepting my request.

ASSISTANT: Let me know your name, to check with your previous reservation.

USER: Sure, my name is Linda Nelson.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for your time, we did not find any reservation on your specified name to change it.

USER: No issues, thank you.

ASSISTANT: Thank you for reaching our service.