The liturgical book, Rite of Penance, includes a section with the heading Penitential Services.
The instructions include “37. Care must be taken to ensure that the faithful do not confuse these celebrations with the celebration of the sacrament of penance.”
Penitential Services have no absolution. They are Celebrations of the Word of God with a gathering of people. “36. It is appropriate after the introductory rites (song, greeting, and opening prayer) one or more biblical readings be chosen with songs, psalms, or periods of silence inserted between them. In the homily … After the homily and reflection on God’s word, it is desirable that the congregation, united in voice and spirit, pray together in a litany or in some other way suited to general participation. At the end the Lord’s Prayer is said … The priest or the minister who presides concludes with a prayer and the dismissal of the people.”
The term “Penance Service” is confusing. “Penance” suggests the sacrament of Penance/Confession/Reconciliation. “Service” suggests a penitential service.