Holy Water is simply water which has been blessed by a priest, which Catholic believe confers the effects of the prayer on anything it touches. In a blessing, the prayer becomes associated with the matter of the sacramental, which in this case is water.
The argument is about whether holy water which has not been blessed according to the traditional formula carries with it the same effect as holy water blessed according to the new formula. The old formula includes a prayer of exorcism:
“I exorcise thee in the name of God the Father almighty, and in the name of Jesus Christ His Son, our Lord, and in the power of the Holy Ghost, that you may be able to put to flight all the power of the enemy, and be able to root out and supplant that enemy and his apostate angels; through the power of our Lord Jesus Christ, who will come to judge the living and the dead and the world by fire.”
The question is: does holy water exorcise if it does not carry with it a prayer of exorcism? My answer is “no”.