Can a Rabbi lose his ordination?
Suppose Reuven is ordained as a Rabbi (receives semicha). His teacher, Rabbi Yaakov, decides that he is learned enough and of the right character to serve as a Rabbinic authority and proclaims that he may do so.
- May Rabbi Yaakov revoke now-Rabbi Reuven's ordination at a later point, if he sees that he was mistaken in giving the ordination?
- If Rabbi Yaakov's ordaining Rabbi, call him Rabbi Avraham, is still alive, can he override Reuven's ordination? That is, can Rabbi Avraham say that he's aware that Rabbi Yaakov approved Reuven's ordination, but that because he feels that Reuven wasn't worthy, he is hereby overruling Reuven's ordination?
- Can a Rabbi who is viewed with greater authority by both Yaakov and Reuven overrule Reuven's ordination, regardless of whether Yaakov agrees or not? Does it matter whether Yaakov is still alive or not?
Assume for the purposes of this question that it is in Talmudic or pre-Talmudic times, when the chain of ordination was unbroken going back to Sinai and one who was ordained actually received certain halachic abilities, rather than merely a title.