Complex sentence: The various profession rites are normally performed by the Abbot, but if the abbot has not been ordained a priest, or if the monastic community is a convent, a hieromonk will perform the service.
Split into simpler sentences: The various profession rites are normally performed by the abbot, but in some traditions he must be a priest before he can do this. In those cases, if he has not been ordained or if the monastery is for women, a hieromonk will perform the service.