V. Points which cannot be settled at the provincial synod are to be referred to Rome.
Any of the brethren who has been summoned to a synod should attend and not deny himself to the holy congregation: for there especially he should know that what will conduce to the good discipline of the Church must be settled. For all faults will be better avoided if more frequent conferences take place between the priests of the Lord, and intimate association is the greatest help alike to improvement and to brotherly love. There, if any questions arise, under the Lord's guidance they will be able to be determined, so that no bad feeling remains, and only a firmer love exists among the brethren.
But if any more important question spring up, such as cannot be settled there under your presidency, brother, send your report and consult us, so that we may write back under the revelation of the Lord, of whose mercy it is that we can do ought, because He has breathed favourably upon us: that by our decision we may vindicate our right of cognizance in accordance with old-established tradition and the respect that is due to the Apostolic See: for as we wish you to exercise your authority in our stead, so we reserve to ourselves points which cannot be decided on the spot and persons who have made appeal to us.
Source: Letters (New Advent)