WCF 30.4.
For the better attaining of these ends, the officers of the church are to proceed by admonition, suspension from the sacrament of the Lord’s Supper for a season; and by excommunication from the Church, according to the nature of the crime, and demerit of the person. (1 Thess. 5:12, 2 Thess. 3:6, 14–15, 1 Cor. 5:4–5, 13, Matt. 18:17, Tit. 3:10)