CCC 1423 It is called the sacrament of conversion because it makes sacramentally present Jesus’ call to conversion, the first step in returning to the Father¹ from whom one has strayed by sin.
It is called the sacrament of Penance, since it consecrates the Christian sinner’s personal and ecclesial steps of conversion, penance, and satisfaction.

1 Cf. Mk 1:15; Lk 15:18.