You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How can I help you?

USER: John Hernandez here, due to sudden changes my exams has been postponed. Can you please change my reservation?

ASSISTANT: Sure, please hold on.

USER: Ok.

ASSISTANT: Thanks for holding on, there is no active reservation on your name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thanks for approaching us. Have a nice day.