Can a Ruthenian Catholic incur automatic excommunication for apostasy?

Can a member of the Ruthenian Catholic Church be automatically excommunicated for apostasy? As far as I know they can't be, as the *Code of Canons of the Eastern Churches* states: >"One who denies a truth which must be believed with divine and catholic faith, or who calls it into doubt, or who totally repudiates the Christian faith, and does not retract it after having been legitimately warned, is to be punished as a heretic or an apostate with a major excommunication" (1436) Does this imply that the Church has to be officially involved in order for the person to be excommunicated?