Roman Catholic dogma holds that it is a sin to baptize a person who has already been baptized. In case of uncertainty about the validity of an earlier attempt at baptism, , a person may be baptized conditionally. In a typical baptism, the minister of the sacrament (usually a deacon or a priest, but sometimes, especially in when the baptized is in imminent danger of death, a layman) says
or words to that effect, explicitly naming the three Persons of the Trinity, while pouring or sprinkling water upon the head of the baptized, or immersing them in water. In a conditional baptism, the minister of the sacrament says
