I am writing to notify you that I have decided to finally devoting all my time and energy on my family. I shall be retiring from my position, effective [date].
I found my stay here as a [position] to be of great pleasure. I have sharpened my professional expertise and allowed my career to thrive. I am grateful for having colleagues who are most outstanding in our field. I will never forget the positive experiences I had in this institution. I wish everybody my warmest regards.
That being said, I would like to request for your assistance in the retirement process. Kindly notify me if additional documentation is needed.
Thank you very much.