Dear xxxxxxx
The purpose of this letter is to inform you that as of (date) my operating hours will be changing to xxx am to xxx pm. With the current hours I am having a hard time finding balance between work responsibilities and family responsibilities. I realize that the new hours are not going to fit with your work schedule and therefore am giving you ample notice for you to find alternative care. The last day if available care for xxxxx will be xxxxx.

Thank you for your understanding,
Gramma