Please accept this letter as resignation of my position as ...(ชื่อตำแหน่ง)with (ชื่อบริษัท). My last day of employment will be January 31st 2012.(วันที่จะลาออก)
There are some personal reasons pertaining to a family business that leads to my decision to resign.
I appreciate the opportunities I have been given during my time with your company.
I wish you and the company success in the future.