The sacrament of Baptism does snatch us from the power of sin and death and brings us into the new life of the children of God, but it does not free us from human weakness and the inclination to sin. That is why we need a place we can be reconciled with God again and again. That place is the sacrament of Penance or Confession (YouCat, 226; CCC, 1425-1426).
What is required for the forgiveness of sins is the person who undergoes conversion and the priest who in God's name gives him absolution from his or her sins (YouCat, 231). Essential elements of every confession are an examination of conscience, contrition, a purpose of amendment, confession, and penance (CCC, 1450-1460; 1490–1492; 1494).
Under normal circumstances, all serious sins that one remembers after making a thorough examination of conscience and that have not yet been confessed can be forgiven only in individual sacramental confession (c.f. CCC, 1457).
Upon reaching the age of reason (seven (7) years or so), a Catholic is required to confess his or her sins. The Church teaches that the faithful is bound by an obligation faithfully to confess serious sins at least once a year. At any rate, one must go to confession before receiving Holy Communion if one has committed a serious sin (c.f. CCC, 1457)
The sacrament of Penance is offered Monday from 5:00pm to 5:30pm for those attending the Monday 5:30pm Mass; Tuesday, Wednesday, Thursday and Friday from 4:00pm to 4:30pm; and on Saturday from 4:30pm - 5:00pm, for those attending the Saturday 5:00pm Mass.