Yosef Karo

“ If one doesn't want to clear the dishes and wants to eat in the sukkah on Shmini Atzeret, a four by four section of sukkah should be taken down to show that they are sitting there not for the mitzvah of sukkah, so that it will not look like adding to the mitzvah. Rem"a: If he wants to sit in the sukkah after the holiday, it is unnecessary to take down any section because it only looks like adding on Shmini Atzeret (Minhagim) . If one must eat for the rest of the day, he must eat in the sukkah because the obligation extends the whole seven days. ”