This article deals with the statement of Pontifical council for legislative texts in the case of the essentials for leaving the Church by a formal act. Not all such acts of defections should be interpreted as a true and willful separation from the Church (e.g .just to escape the obligation to pay the church tax most likely is not an act of reneging of the doctrinal teaching). Therefore the reason of defection from the Church has always to be examined. The point has close connection with marriage law by reason that a fallen away Catholic does not need to observe the canonical form of marriage. In the cases of the declaration of the nullity of marriage, it is necessary to examine, whether or not there is a true separation from the Church. The attitude of German bishops, according to which all the fallen away Catholics incur ipso facto an excommunication, contradicts the statement of the Pontifical council. Excommunication cannot be imposed validly for refusal to pay the church tax. The author is suggesting necessary changes of the relevant prescripts of the Codex and issuing new corrected proceeding how to treat Catholics who had fallen away from the Church.