Hoshana Rabbah is known as the day of the final sealing of judgment, which began on Rosh Hashanah. During the festival of Sukkot the world is judged for water. The seventh day of the festival is the final sealing and since human life depends on water, Hoshana Rabbah is somewhat similar to Yom Kippur. Hence there are additional prayers and requests for repentance as on Yom Kippur. In this spirit, the cantor wears a kittel as on the High Holidays. Hoshana Rabbah has an interesting status as sort of a High Holiday (because of it being the final day for judgment) and in between a Chol HaMoed and full-fledged Yom Tov, and in this spirit the cantor, in the Ashkenazic tradition, recites the service using High Holiday, Festival, Weekday, and Sabbath melodies interchangeably.