Canon 400

Can. 400 §1. Unless the Apostolic See has established otherwise, during the year in which he is bound to submit a report to the Supreme Pontiff, a diocesan bishop is to go to Rome to venerate the tombs of the Blessed Apostles Peter and Paul and to present himself to the Roman Pontiff.

Can. 400 §2. A bishop is to satisfy the above-mentioned obligation personally unless he is legitimately impeded. In that case, he is to satisfy it through his coadjutor, if he has one, or auxiliary, or a suitable priest of his presbyterium who resides in his diocese.

Can. 400 §3. An apostolic vicar can satisfy this obligation through a proxy, even one living in Rome. This obligation does not bind an apostolic prefect.