Similar to acceptance of inheritance, a written declaration (public deed )is made, received by a notary public or the clerk of the court of the district in which the succession was opened , and entered in the register of succession. Through this act the named states they do not want to accept the inheritance .
However, acceptance is never revocable ( or renounced ,according to the law ) it may be waived , provided that in the meantime acceptance has not intervened by another named inheritor of greater degree. For example, if the child renounces and the brother of the deceased accepts, the child will not be able to revoke the waiver. If the named are two brothers, one renounces and the other accepts , the one who renounces may be subject to revocation within the time allowed. With the declaration of renunciation, the named does not lose the right to accept the inheritance : for they may withdraw the renunciation. The acceptance therefore takes precedence over the declaration of renunciation.

Terms. The renunciation may be carried out as long as the right to accept hasn’t expired (ten years after the opening of the succession or the birth of the named party if not yet born at the time of opening of the inheritance). After the period of limitation the named party loses the right to accept the inheritance.
The only practical difference to the inheritor is fiscal: the act of renunciation (both in front of a notary or the clerk of the court ) includes a fixed registration duty of € 168. If you leave the prescribed right to acceptance taxes are not paid.

How it works. It is a unilateral negotiation and a formal written response (the acceptance of the renunciation not required. It is valid from the moment in which the named submits it to the notary or the clerk of the court). It is not possible to be partially surrendered or be subject to terms or conditions, under penalty of nullity. Those who renounce to inherit are treated as if they had never been named since the death of the deceased.

By renouncing the inheritance it is devolved to the other parties entitled to it , in a different way from legitimate testamentary successions. So in the legitimate succession, the share of the renounced goes to increase the shares of those who would contest to inherit if there is no representation . This means, for example, that if the named are his wife and two children , where the mother exercised the waiver this would proportionately increase the share of the children. If instead one of the sons renounces, this would increase the share of the mother and the other child. The representation only comes into play if you are the legitimate children or siblings of the deceased.
If the only person entitled to the inheritance renounces (for example, because there is only one child), the legacy is devolved to those who would be responsible in the event that they were missing. In other words those who would take over as heirs if he were not there.