Prümmer, O.P.: "Private exorcism may be performed by anyone"

[Geremia]

Prümmer, O.P., Handbook of Moral Theology (PDF pp. 269-70):

Art. 6. Adjuration

1. Definition. Adjuration is the use one makes of the reverence, fear, or love which another has for the name of God or a holy thing to induce him to do or omit something.

In adjuration, therefore, one person tries to obtain something from another in virtue of the latter's reverence or fear of God. All who know God may be adjured — that is to say, God Himself, Christ, our Lady, the saints, men on earth, the devils.

Adjuration is solemn if made with the ceremonies prescribed by the Church; otherwise, it is simple. It is precatory if made in the form of a request; it is comminatory (imperative) if accompanied by commands.

Principle. Adjuration which fulfills the requisite conditions is an act of religion and therefore lawful and morally good.

By such an act recognition is made of God's majesty. Furthermore, it is an act which has often been used by the Church.

The requisite conditions for lawful adjuration are the same as those for a lawful oath; namely truth, justice, right judgment.

Truth demands that the agent should not deceive the individual who is adjured.

Justice demands that he intend something that is lawful.

Right judgment demands that adjuration should be accompanied by due reverence.

1. Exorcism. In its strict sense, exorcism is the expulsion of the devil from one possessed; in its wide sense, it includes the nullifying of the devil's influence in any creature. In a solemn exorcism, understood in its strict sense, the directions of the Church must be scrupulously observed. It is of prime importance to obtain the ordinary's permission since it is his function to decide whether it is a genuine case of diabolical possession and whether it is fitting to perform the exorcism solemnly. [See [1917] CCL, Can. 1151ff.] Private exorcism may be performed by anyone, but its influence is greater if exercised by one who has received the Order of exorcist.