[quote=] Can. 148 Unless the law provides otherwise, the provision of an office is the prerogative of the authority which is competent to establish, change or suppress the office.
[quote=] CHAPTER IV : LOSS OF THE CLERICAL STATE
Can. 290 Sacred ordination once validly received never becomes invalid. A cleric, however, loses the clerical state:
1° by a judgement of a court or an administrative decree, declaring the ordination invalid;
2° by the penalty of dismissal lawfully imposed;
3° by a rescript of the Apostolic See; this rescript, however, is granted to deacons only for grave reasons and to priests only for the gravest of reasons.
Can. 291 Apart from the cases mentioned in can. 290, n. 1, the loss of the clerical state does not carry with it a dispensation from the obligation of celibacy, which is granted solely by the Roman Pontiff.
Can. 292 A cleric who loses the clerical state in accordance with the law, loses thereby the rights that are proper to the clerical state and is no longer bound by any obligations of the clerical state, without prejudice to can. 291. He is prohibited from exercising the power of order, without prejudice to can. 976. He is automatically deprived of all offices and roles and of any delegated power.
Can. 293 A cleric who has lost the clerical state cannot be enrolled as a cleric again save by rescript of the Apostolic See.
[quote=] Can. 908 Catholic priests are forbidden to concelebrate the Eucharist with priests or ministers of Churches or ecclesial communities which are not in full communion with the catholic Church.