“Confirmation perfects baptismal grace; it is the sacrament that bestows the Holy Spirit to root us more deeply in divine sonship, to unite us more firmly with Christ, to strengthen our bond with the Church, to associate us more closely with its mission, and to help us bear witness to the Christian faith through words accompanied by deeds”.
“Confirmation, like Baptism, imprints on the soul of the Christian a spiritual and indelible mark; therefore this sacrament can only be received once in a lifetime”.(Catechism of the Catholic Church, 1285–1314).
For further information about the requirements, please refer to the link below :