If one skipped Yaaleh v’yavo on R”C, remembered during Modim, and went back to Yaaleh v’yavo instead of reverting to the beginning of the bracha of Retzei as is required, does he need to daven again? [Since he skipped a good chunk of the bracha of Retzei.]
If he has already finished davening he has to say S”E again, since he didn’t say the bracha correctly.
Rivivos Eprayim 2-185(10) in the name of R’ M Feinstein zt”l, and Mevakshe Torah Sivan 5755 Sian 163 in the name R S. Z. Auerbach zt”l. Eishei Yisroel 39ftnt. 42. (We will have to say that the main part of the bracha is missing here.)