Dropping from full time to part time at work

Write a letter saying that I am dropping from full time to part time at work.
Include that I am in school and thank for still being able to be part of the company and thanks for letting me keep my job with the new schedule, Also include that my last full time day was Monday September 16, 2019 also apologize for the inconvenience. Also include that I will of course work as hard as always, and put forth every effort on my part time schedule. If there is anything else I can do, I would be happy to assist.