From the playbook of Bl. Pope John XXIII

This is from Bl. Pope John XXIII's opening speech to the Second Vatican Council.  These two paragraphs are under the heading of How to Repress Errors.  I would add:  with Charity.

At the outset of the Second Vatican Council, it is evident, as always, that the truth of the Lord will remain forever. We see, in fact, as one age succeeds another, that the opinions of men follow one another and exclude each other. And often errors vanish as quickly as they arise, like fog before the sun. The Church has always opposed these errors. Frequently she has condemned them with the greatest severity. Nowadays however, the Spouse of Christ prefers to make use of the medicine of mercy rather than that of severity. She considers that she meets the needs of the present day by demonstrating the validity of her teaching rather than by condemnations.

Not, certainly, that there is a lack of fallacious teaching, opinions, and dangerous concepts to be guarded against an dissipated. But these are so obviously in contrast with the right norm of honesty, and have produced such lethal fruits that by now it would seem that men of themselves are inclined to condemn them, particularly those ways of life which despise God and His law or place excessive confidence in technical progress and a well-being based exclusively on the comforts of life. They are ever more deeply convinced of the paramount dignity of the human person and of his perfection as well as of the duties which that implies. Even more important, experience has taught men that violence inflicted on others, the might of arms, and political domination, are of no help at all in finding a happy solution to the grave problems which afflict them.

That being so, the Catholic Church, raising the torch of religious truth by means of this Ecumenical Council, desires to show herself to be the loving mother of all, benign, patient, full of mercy and goodness toward the brethren who are separated from her. To mankind, oppressed by so many difficulties, the Church says, as Peter said to the poor who begged alms from him: "I have neither gold nor silver, but what I have I give you; in the name of Jesus Christ of Nazareth, rise and walk" (Acts 3:6). In other words, the Church does not offer to the men of today riches that pass, nor does she promise them merely earthly happiness. But she distributes to them the goods of divine grace which, raising men to the dignity of sons of God, are the most efficacious safeguards and aids toward a more human life. She opens the fountain of her life-giving doctrine which allows men, enlightened by the light of Christ, to understand well what they really are, what their lofty dignity and their purpose are, and, finally, through her children, she spreads everywhere the fullness of Christian charity, than which nothing is more effective in eradicating the seeds of discord, nothing more efficacious in promoting concord, just peace, and the brotherly unity of all.

Now, Bl. Pope John XXIII was not addressing liturgical mistakes here, but I think the principles apply to such issues.