Canon 29 A bishop may not be reduced to presbyter

To bring a bishop to the rank of a presbyter is sacrilege. And if some just cause removes those men from the exercise of the episcopate, they ought not to hold even the place of a presbyter. But if they were removed from the dignity without any charge, they shall return to the dignity of the episcopate. Anatolius, the most reverent archbishop of Constantinople, said: These who are said to have come down from the episcopal dignity to the order of presbyter, if they are condemned for some reasonable causes, are rightly not worthy to be even within the honour of a presbyter; but if they were brought down to the lesser rank without some reasonable cause, they are entitled, if indeed they appear blameless, to take back both the dignity and the priesthood of the episcopate.