In our diocese we have a Bishop Emeritus who still takes the place of the current Bishop Earl i.e. Bishop Emeritus Carl Mengling, still confers Confirmation on the candidates when the current Bishop is attending something else. We attended our granddaughter’s confirmation last year when Bishop Emeritus Carl performed the rites, Diocese of Lansing, MI. I do not know what other activity Bishop Earl was involved in at that time.
Well, in terms of Holy Orders, a bishop is always a bishop. But a pope is not always a pope.