Thank you for your question of changing liturgical texts.
Canon 846 of the Code of Canon Law states:
- The liturgical books approved by the competent authority are to be faithfully observed in the celebration of the sacraments; therefore no one on personal authority may add, remove or change anything in them.
Number 22 of the Constitution on the Sacred Liturgy states:
- 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.
- 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.
- Therefore, absolutely no other person, not even a priest, may add, remove, or change anything in the liturgy on his own authority.
Therefore, no one may change any approved and confirmed liturgical text. This includes, but is not limited to the Lectionary for Mass and the Sacramentary.