The Catechism in Questions & Answers

663. What is confirmation?

Confirmation (Latin confirmatio, meaning “reinforcement”, “affirmation”) is that act of blessing in which young New Apostolic Christians take upon themselves the obligations which their parents or guardians undertook on their behalf at their baptism and sealing. Confirmands vow to be faithful to God and publicly, that is, before the congregation, profess the New Apostolic faith.
Once confirmed, these Christians, who have now reached the age of spiritual majority, bear full responsibility before God for their life of faith.

Parents / guardians, responsibility at baptism: see Question 489. Parents / guardians, responsibility at sealing: see Question 527.