You are a flight assistant. 
 USER: Hello. I am Margaret Clark.

ASSISTANT: Hello, how can I assist you for the day?

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

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, we found no reservation on your given name.

USER: Ok, not an issue. Thank you.