Beatification means to declare a person (until now called the Servant of God or Venerable) as a blessed.
Beatification takes place during the Mass. It is an act by which – after the end of the prescribed process – the Pope allows to give to a Servant of God the public church cult at certain area and with prescribed manners, e.g. in the diocese which led the process, or in the whole nation to which the Servant of God belonged, or in the certain group of faithful (e.g. in a monastic order). The Pope also states the date of the celebrating of the liturgical feast day of a new blessed.
Beatification itself is done by reading the Ecclesiastical letter, signed by Pope and read by Pope´s Nuncio. The beatified person is forever inscribed in the liturgical calendar of the local Church or monastic society. The relic of beatified use to be given to the public veneration of the faithful.
The whole process finishes by the canonization. To accomplish it, the Church investigates the miracle assumptively resulting from the intercession of the blessed.
From the theological point of view it is not considered as an infallible Pope´s statement; it means the inscribing a person to the list of the beatified and a permission of the public cult. Meanwhile the canonization is considered as infallible statement of Pope – in the role of the Doctor of the Church – and it is not only the permission of the public cult, the public cult is commanded for the whole Church.
“By canonizing some of the faithful, i.e., by solemnly proclaiming that they practised heroic virtue and lived in fidelity to God´s grace, the Church recognizes the power of the Spirit of holiness within her sustains the hope of believers by proposing the saints to them as models and intercessors. The saints have always been the source of origin of renewal in the most difficult moments in the Church´s history. Indeed, ´holiness is the hidden source and infallible measure of her apostolic activity and missionary zeal´.” (CCC 828)
“When the Church keeps the memorials of martyrs and other saints during the annual cycle, she proclaims the Paschal mystery in those ´who have suffered and have been glorified with Christ. She proposes them to the faithful as examples who draw all men to the Father through Christ, and through their merits she begs for God´s favours.” (CCC 1173)