Canon 701

A concelebration between bishops and presbyters of different

Churches sui iuris for a just cause, especially that of fostering

charity, and for the sake of manifesting unity between the Churches, can be done with the permission of the eparchial bishop,

while observing all the prescriptions of the liturgical books of

the principal celebrant, having removed any liturgical syncretism

and wearing the appropriate vestments and insignia of his own

Church sui iuris.