§1. Not only the parties who consider themselves aggrieved can introduce a complaint of nullity but also the promoter of justice and the defender of the bond whenever they have the right to intervene.
§2. The judge can retract or emend ex officio a null sentence, which that judge has rendered, within the time limit for acting established by can. 1623 unless an appeal together with a complaint of nullity has been introduced in the meantime or the nullity has been sanated through the expiration of the time limit mentioned in can. 1623.
Source: Code of Canon Law (Vatican.va)