If called again to preside over a ward, his previous ordination is reactivated. When he is released, it becomes dormant again. Inherent in the ordination to be bishop is both the right and the obligation to be directed by inspiration. The bishop has the power to discern by the Spirit what he is to do. Revelation is the one credential that all bishops have in common.
Bishops come from many cultures, many occupations.
They vary in experience, personality, and age, but they do not differ in their right to be guided spiritually. Years ago a friend of mine went to a large university to study under the ranking authority in the field of counseling and guidance. This professor quickly took an interest in this personable, intelligent young Latter-day Saint. He attracted attention as he moved through the course work required for a doctor's degree. He chose the Latter-day Saint bishop as the subject for his dissertation.