During Great Lent a number of changes in the office take place. On Tuesday, Wednesday and Thursday, after the three fixed psalms, the Reader says a kathisma from the Psalter. The Troparion of the Day is replaced by special Lenten hymns that are chanted with prostrations. Then the psalm verses that follow the Theotokion, which are normally read, are instead sung by the choir. The Kontakion is also replaced by special Lenten hymns which are sung. Near the end of the Hour, the Prayer of St. Ephraim is said, with prostrations.