Good quality and properly written Natural Law Trusts are irrevocable. This means the settlor relinquishes all further control of the trust at its inception. However, the same person can play the role of the manager. The manager can make changes and perform actions in that role, assuming s/he has determined the rules written into the trust and follows them. If you want to give a certain role independent powers, then you can also write that into the trust. You can administer the trust any way you want, as long as it maintains certain basic structural principles.