Sacrosanctum Concilium (Constitution on the Sactitled Liturgy)
III. The Reform of the Sacred Liturgy
A) General norms …
22. 1. Regulation of the sacred liturgy depends solely on the authority of the Church, that is, on the Apostolic See and, as laws may determine, on the bishop.
2. In virtue of power conceded by the law, the regulation of the liturgy within certain defined limits belongs also to various kinds of competent territorial bodies of bishops legitimately established.
3. Therefore no other person, even if he be a priest, may add, remove, or change anything in the liturgy...