One part of my answer on the question of what words bring about Transsubstantiation, I am entirely certain we are talking about the words: This is my Body…This is my Blood".
We are not talking about words which have some subjunctive mood in them, like" Pray, brethren, that our sacrifice
May be acceptable to God, the almighty Father
May the Lord accept the sacrifice at your hands
For the praise and glory of his name,
For our good and the good of all his Church",
or "Bless and approve our offering: make it acceptable to you, an offering in spirit and in truth. Let it become for us the body and blood of Jesus Christ, your only Son, Our Lord.
Those are not the words of institution, the words of Christ at the Last Supper.
Every sacrament has what is called “Matter” and “Form”, so in Baptism, the “matter” is the water, and the “form” are the words"
“I baptise you, in the name…”
In the Eucharist, we have matter and form: The matter is the bread and wine, the elements. The form are the words, “This is my Body”, “This is my Blood…”
As for Epiclesis, the Church teaches ‘de fide’ that transubstantiation is effected by Christ words. as is clear from the fact that in the Roman Missal there is no true epiclesis. Catholic theologians teach that the sacrifice in all its essentials is complete as soon as the words of institution have been pronounced over the chalice, that is, after the two-fold consecration of the bread and wine has taken place.
What are the words of institution - the words Christ used when instituting this Sacrament.