Transitions at work are never easy or simple. They are, however, a fact that every individual and organization will have to deal with at some point. Employees leave your team or organization. You choose to leave your team or organization. As the saying goes, the only constant in life is change.
When you are the individual making the move, I have found it to be helpful to create transition documents for both the position you are leaving and the position you are moving in to. The outgoing document will help the organization you are leaving know where you are leaving the work you were being paid to do and the incoming document will help you stay focused on creating a solid foundation for success in your new role.