While "clerics and members of institutes of consecrated life are bound to observe their own rite faithfully,"[REF] 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".
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 [REF].