structural:summarization, quality:corruption
Bi-ritual faculties

While "clerics and members of institutes of consecrated life are bound to observe their own rite faithfully", priests are occasionally given permission to celebrate the liturgy of a rite other than the priest's own rite, by what is known as a grant of "biritual faculties". The reason for this permission is usually the service of Catholics who have no priest of their own rite. Thus priests of the Syro-Malabar Church working as missionaries in areas of India in which there are no structures of their own Church, are authorized to use the Roman Rite in those areas, and Latin priests are, after due preparation, given permission to use an Eastern rite for the service of members of an Eastern Catholic Church living in a country in which there are no priests of their own particular Church. Popes are permitted to celebrate a Mass or Divine Liturgy of any rite in testament to the Catholic Church's universal nature. John Paul II celebrated the Divine Liturgy in Ukraine during his pontificate.

For a just cause, and with the permission of the local bishop, priests of different autonomous ritual Churches may concelebrate; however, the rite of the principal celebrant is used whilst each priest wears the vestments of his own rite. No indult of bi-ritualism is required for this.

Biritual faculties may concern not only clergy but also religious, enabling them to become members of an institute of an autonomous Church other than their own.