If somebody forgot to recite "Reseh" in Birkat Ha’mazon after one of the first two Shabbat meals (as opposed to Se’uda Shelishit), or to recite "Ya’aleh Ve’yabo" on the first night of Sukkot or first night of Pesach, he must repeat Birkat Ha’mazon.
The Kaf Ha’haim (Rav Yaakob Haim Sofer, 1870-1939) ruled that this Halacha applies only to men, and not to women. Since there were those who questioned whether women are obligated in Birkat Ha’mazon as men are, the Kaf Ha’haim felt that women do not have to repeat Birkat Ha’mazon in the cases mentioned above. However, this is not the accepted opinion. Hacham Ovadia Yosef (in Yabia Omer, vol. 6, and Yehaveh Da’at 2:20) writes that Halacha does not distinguish at all between the obligation men and that of women with regard to Birkat Ha’mazon, and this Misva applies equally to both. The only difference is that on the first night of Sukkot, a woman does not have to repeat Birkat Ha’mazon if she forgot to add "Ya’aleh Ve’yabo." Since women are not obligated to eat bread on the first night of Sukkot as men are, they do not repeat Birkat Ha’mazon in such a case. However, with regard to "Reseh" after one of the first two Shabbat meals, or "Ya’aleh Ve’yabo" on the first night of Pesach, both men and women must repeat Birkat Ha’mazon if the required insert was mistakenly omitted.
Summary: One who forgot to add "Reseh" in Birkat Ha’mazon after one of the first two Shabbat meals, or to add "Ya’aleh Ve’yabo" on the first night of Sukkot or first night of Pesach, must repeat Birkat Ha’mazon. This applies to both men and women, except that on the first night of Sukkot, a woman does not have to repeat Birkat Ha’mazon if she forgot to add "Ya’aleh Ve’yabo."
