328. Other Mistakes in Davening

Tefillah u’Birkas Kohanim 10:14

If someone made a mistake and didn’t recite havdalah in the bracha of chonein hadaas, he should finish davening without going back at all. The same is true if one omitted al hanissim on Chanukah or Purim, or aneinu on a fast day; one need not repeat Shemoneh Esrei, neither an individual nor the shaliach tzibbur. If one realizes he forgot aneinu before taking his three steps back, he should say, “Answer us because You are the One Who hears prayer, redeems, and saves in all times of trouble and distress,” followed by “May the words of my mouth....”

Tefillah u’Birkas Kohanim 10:15

If someone neglected to daven mincha on Friday afternoon, he recites the Shabbos maariv twice. He acts likewise on a yom tov. If one neglects to daven mincha on Shabbos or yom tov, he recites the weekday maariv twice. He recites havdalah in the first of these two Shemoneh Esreis but not in the second. However, if he recited it in both - or in neither - he still fulfills his obligation. If he did not recite havdalah in the first Shemoneh Esrei but he did in the second, then he must go back and recite a third Shemoneh Esrei. This is because the first one doesn’t count, having been recited before the valid maariv. When one has two Shemoneh Esreis to recite – even shacharis and musaf – he should not do so back-to-back. Rather, he should pause between prayers in order to clear his mind.