Can. 1161 §1. The radical sanation of an invalid marriage is its convalidation without the renewal of consent, which is granted by competent authority and entails the dispensation from an impediment, if there is one, and from canonical form, if it was not observed, and the retroactivity of canonical effects.
§2. Convalidation occurs at the moment of the granting of the favor. Retroactivity, however, is understood to extend to the moment of the celebration of the marriage unless other provision is expressly made.
Can. 1165 §1. The Apostolic See can grant a radical sanation.
§2. The diocesan bishop can grant a radical sanation in individual cases even if there are several reasons for nullity in the same marriage, after the conditions mentioned in can. 1125 for the sanation of a mixed marriage have been fulfilled. He cannot grant one, however, if there is an impediment whose dispensation is can. 1078, §2, or if it concerns an impediment of natural law or divine positive law which has now ceased.
Can. 1125 The local ordinary can grant a permission of this kind if there is a just and reasonable cause. He is not to grant it unless the following conditions have been fulfilled:
1/ the Catholic party is to declare that he or she is prepared to remove dangers of defecting from the faith and is to make a sincere promise to do all in his or her power so that all offspring are baptized and brought up in the Catholic Church;
2/ the other party is to be informed at an appropriate time about the promises which the Catholic party is to make, in such a way that it is certain that he or she is truly aware of the promise and obligation of the Catholic party;
3/ both parties are to be instructed about the purposes and essential properties of marriage which neither of the contracting parties is to exclude.
