Yosef Karo, Translation:Shulchan Aruch — Orach Chaim 619…
“ The prayer leader says "And the whole nation was forgiven..." three times, and the community says "And God said 'I have forgiven them as you have said'" three times (Minhagim) . Nobody should change the practice of the town, even with respect to melodies and piyyutim that they say there (Mahari"l) . ”
