A woman who realizes in the middle of the Amida that she skipped or made a mistake in one of the thirteen middle berakhot must return to that berakha and continue praying from that point on, in the correct order. Even though she repeats the berakhot that she already recited, since everything after that berakha was not recited in order, it is as if she did not say them at all, and she must recite them again in their correct sequence (Berakhot 34a according to Rashbam’s interpretation; SA 119:3).
If she skips or errs in one of the first three berakhot or one of the last three berakhot, either by reciting the wrong words in one of these berakhot or by skipping one of them and incorrectly starting the next one, she must go back to the beginning of the three berakhot. Since the first three berakhot possess one theme, as do the last three berakhot (see above, 12:9), each section is considered one unit. Therefore, anyone who makes a mistake in one berakha is considered to have erred in all of them and must repeat all three from the beginning (Berakhot 34a; Rema 114:6; an example of this law appears below in section 8).
One who completes the Amida and then remembers that she omitted or erred in one of the berakhot must repeat the entire Amida. Even if she has not yet taken three steps back, if she finished the prayers of supplication and is about to take steps backwards, she must return to the beginning of the Amida (SA 117:5).
If one interrupts Shemoneh Esrei in the middle, whether verbally or silently, and the interruption is brief, she continues praying from the point where she stopped. However, if the interruption is long enough that she could have finished praying the entire Amida from beginning to end, she returns to the beginning of the Amida. Some say that there is no difference between an intentional interruption and one due to circumstances beyond one’s control. In either case, since there was enough time for her to finish the entire Amida, she starts from the beginning (SA 104:5, and this is the Sephardic custom). Others maintain that she only returns to the beginning of the Amida if the interruption was due to circumstances beyond her control; however, if she freely interrupted, even for a long time, she returns to the place where she stopped (Rema 65:1; MB 104:16; this is the Ashkenazic custom). We will explain when one may interrupt when necessary below (14:1-2).