§ 1. One who in furtherance of an offence did something or failed to do something but then, involuntarily, did not complete the offence, is not bound by the penalty prescribed for the completed offence, unless the law or a precept provides otherwise. § 2. If the acts or the omissions of their nature lead to the carrying out of the offence, the person responsible may be subjected to a penance or to a penal remedy, unless he or she had spontaneously desisted from the offence which had been initiated. However, if scandal or other serious harm or danger has resulted, the perpetrator, even though spontaneously desisting, may be punished by a just penalty, but of a lesser kind than that determined for the completed crime.
Source: Code of Canon Law (Vatican.va)