You are a flight assistant. 
 USER: Hi, I am Cynthia Taylor. I need  to change my existing reservation due to postpone of my exams.

ASSISTANT: Hello, Cynthia Taylor. Sure. Please give us some time for checking your reservation details. OK.

USER: Ok.

ASSISTANT: Sorry to inform you that after checking with our database, We found that there is no reservation on Cynthia Taylor. Thank you, For making an inquiry with us regarding change reservation. Have a great day.

USER: Thank you.