376. When No Kohanim are Present

Tefillah u’Birkas Kohanim 15:10

If there is no kohein in the congregation other than the shaliach tzibbur, he should not duchen. If he knows that he can duchen and then resume davening without confusion, then he may do so. If there are no kohanim at all, when the shaliach tzibbur reaches the bracha of Sim Shalom, he says, “Our God and God of our fathers, bless us with the three-fold blessing in the Torah, which was written by Your servant Moses and recited by Aaron and his sons, the kohanim, Your holy people, as it says: May God bless you and guard you; May God shine His countenance on you and be gracious to you; May God turn His countenance toward you and grant you peace. They will place My Name on the children of Israel and I will bless them.” The congregation does not respond “Amen” when these blessings are recited by a non-kohein shaliach tzibbur. After reciting this, the shaliach tzibbur continues with Sim Shalom.

Tefillah u’Birkas Kohanim 15:11                                                                  

If a kohein recited the birkas kohanim in one shul and then went to another shul, where he found the congregation in the middle of Shemoneh Esrei before birkas kohanim, he should bless them. A kohein may duchen multiple times per day. If a kohein doesn’t move from his place to ascend the platform when the shaliach tzibbur recites the bracha of R'tzei, he may not duchen during that service. If he got up but did not reach the platform until after the shaliach tzibbur finished R'tzei, he may still duchen.