Canon 394

After it has been validly received, sacred ordination never becomes invalid. A cleric, however, loses the clerical state: (1)

by a judicial sentence or administrative decree which declares

the invalidity of sacred ordination; (2) by the legitimate infliction of the penalty of dismissal; (3) by a rescript of the

Apostolic See or in accordance with the norm of can. 397, of the

patriarch; this rescript cannot be granted licitly by the patriarch and is not granted by the Apostolic See to deacons without

serious cause nor to presbyters without most serious cause.