Christus Dominus §21

²¹ Since the pastoral office of bishops is so important and weighty, diocesan bishops and others regarded in law as their equals, who have become less capable of fulfilling their duties properly because of the increasing burden of age or some other serious reason, are earnestly requested to offer their resignation from office either at their own initiative or upon the invitation of the competent authority. If the competent authority should accept the resignation, it will make provision both for the suitable support of those who have resigned and for special rights to be accorded them. II. Diocesan Boundaries