Netilas Yodayim
11. The poskim discuss whether a Kohen in the middle of his Shemoneh Esrei who needs to interrupt for Birkas Kohanim must wash his hands before Birkas Kohanim (שאילת יעב''ץ א' מ''ב). However, the accepted minhag is not to wash in the middle of davening. If he did not wash his hands, he can still do Birkas Kohanim and rely on the opinion that his netilas yodayim before Shacharis is enough (חיי אדם כלל ל''ב סכ''ו, קצשו''ע), as we mentioned (Issue 355, par. 28).
First Opinion
12. There is a machlokes haposkim whether a Kohen in the middle of Shemoneh Esrei should do Birkas Kohanim, based on two opinions.
13. No other Kohanim. Some hold that if there are no other Kohanim in shul, a Kohen in the middle of Shemoneh Esrei should do Birkas Kohanim so that the mitzva will not be missed. This is because Birkas Kohanim is d’oraisa, while interrupting mid-Shemoneh Esrei is only an issue d’rabanan (שו''ת הרדב''ז ח''ד סי' רצ''ז הובא במג''א סק''מ).
14. He should do this by shifting slightly when the shliach tzibbur reaches רצה; then, after the shliach tzibbur says the bracha of “הטוב שמך,” he should stop his Shemoneh Esrei wherever he is and go up for Birkas Kohanim; then, after he finishes Birkas Kohanim, he should go back to his spot to finish his Shemoneh Esrei.
15. Other Kohanim present. However, if there is/are another Kohen/other Kohanim there to do Birkas Kohanim, a Kohen in the middle of Shemoneh Esrei should not interrupt for Birkas Kohanim, which he is not obligated in if he did not begin moving forward at רצה. Also, the call of “Kohanim!” is not directed at Kohanim who are still davening Shemoneh Esrei (רדב''ז שם).
Second Opinion
16. Other brachos of Shemoneh Esrei. Others argue. They hold a Kohen should never interrupt his Shemoneh Esrei to do Birkas Kohanim if he is up to one of the other brachos of Shemoneh Esrei (א''ר סק''ג, יעב''ץ בסידורו, שו''ת הלכות קטנות סי' ס''ד). Many poskim follow this opinion.
17. After הודאה. However, if the Kohen has finished the bracha of הודאה together with the shliach tzibbur, where Birkas Kohanim is said, he can do Birkas Kohanim before שים שלום (שם).
18. The Kohen should do this if he estimates during his tefilla that he will reach the end of הודאה together with the shliach tzibbur. In that case, he should move forward slightly when the shliach tzibbur gets to רצה; then, when he reaches the end of the bracha of הודאה, he should walk up to the front to do Birkas Kohanim; then, he should return to his tefilla afterward without getting mixed up (מ''ב ס''ק ק''ו).
