On Wednesday of the sixth week of Pascha, we celebrate the Leave-taking of the Feast. While most Feasts have their Leave-taking on the eighth day, Pascha, the Feast of Feasts, has its Leave-taking on the thirty-ninth day.
The fortieth day is the Feast of the Lord’s Ascension, which marks the end of the Lord’s physical presence on earth. He does not abandon us, however. He has promised to be with us always, even until the end of the age (MT 20:28). As we sing in the Kontakion for Ascension, “Thou didst ascend in glory, O Christ our God, not being parted from those who love Thee, but remaining with them and crying: I am with you and no one will be against you.” There is a similar thought expressed in the Troparion for the Dormition: “In falling asleep, you did not forsake the world, O Theotokos.”
The services today are celebrated just as on the day of Pascha itself. The daily readings from Holy Scripture, of course, will differ. After the Dismissal at Liturgy, the paschal hymns are no longer sung. The prayer “O Heavenly King” is not said or sung until Pentecost. The Winding Sheet (Plaschanitsa) is taken from the altar and is put in its proper place. Even though today is a Wednesday, fish, wine, and oil are permitted.
Today we also commemorate the Finding of the Icon of the Mother of God “Of the Meeting” in Kalamata in the Peloponnesus.
~Orthodox Church in America (OCA), https://www.oca.org/saints/lives/2022/06/01/41-leavetaking-of-pascha.