§1. The Roman Rota judges: 1/ in second instance, cases which have been adjudicated by the ordinary tribunals of first instance and brought before the Holy See through legitimate appeal; 2/ in third or further instance, cases which the Roman Rota or any other tribunals have already adjudicated unless the matter is a res iudicata.
§2. This tribunal also judges in first instance the cases mentioned in can. 1405, §3 and others which the Roman Pontiff, either motu proprio or at the request of the parties, has called to his own tribunal and entrusted to the Roman Rota; unless the rescript entrusting the function provides otherwise, the Rota also judges these cases in second and further instance.
Source: Code of Canon Law (Vatican.va)