Walling Off - Αποτείχιση

“Those who separate themselves from communion with their Archpriest President, due to any heresy condemned by Holy Council or by Fathers, that he currently preaches in public, openly to the Church, these persons who Wall themselves Off from any Communion with such accused Bishop prior to any official condemnation by Council, not only are not subject to any canonical penalty but are also worthy of the honour befitting the Orthodox, because they have condemned, not true “Bishops”, but False-Bishops and False-Teachers. These Walled Off believers have not severed the unity of the Church by schism, but they combat to protect the Church from schisms and divisions.” 

(15th Canon of the Holy First-Second Apostolic Council held in 861 by St Photius the Great, Patriarch of Constantinople).