Canon 112. §1 After the reception of baptism, the following are enrolled in another Church sui iuris:

1° one who has obtained permission from the Apostolic See;

2° a spouse who, on entering marriage or during its course, has declared that he or she is transferring to the Church ‘sui iuris’ of the other spouse; on the dissolution of the marriage, however, that person may freely return to the Latin Church;

3° the children of those mentioned in nn. 1 and 2 who have not completed their fourteenth year, and likewise in a mixed marriage the children of a Catholic party who has lawfully transferred to another Church ‘sui iuris’; on completion of their fourteenth year, however, they may return to the Latin Church.

§2. The practice, however long standing, of receiving the sacraments according to the rite of another Church ‘sui iuris’, does not bring with it membership of that Church.

§3. Each transfer to another Church ‘sui iuris’ is valid from the moment of the declaration made in the presence of the local ordinary of the said Church or of its
pastor or of the priest delegated by one of them and of two witnesses, unless a rescript of the Apostolic See disposes otherwise; and is noted in the baptismal register.
[revised wording according to m.p. De concordia inter Codices, 31.V.2016]