Consistory - or Council - is the governing body of the church composed of the ministers, the elders and the deacons. "Consistory" is the term used by the Reformed Church in America while "Council" is used by the Christian Reformed Church in North America. Maple Avenue is a "union church"- meaning that we are affiliated with both denominations.
Members of Consistory/Council are elected to terms of three years, and once they are ordained, they are always ordained to that position. Being "installed" means that elders/deacons are actively serving at this specific church. So, ordination happens once, but installation can happen as many times as one is elected to serve.
The "Greater Consistory" consists of past and present members of council/consistory, and may be called upon in matters of special importance as an advisory voice.
From the Liturgy for the Ordination & Installation of Deacons and Elders:
The word "elder" is often translated as "overseer." The office of the elder is "one of servanthood and service representing Christ through the action of the Holy Spirit," and elders are "to have supervision of the church entrusted to them. They are set apart for a ministry of watchful and responsible care for all matters relating to the welfare and good order of the church" (The Book of Church Order, RCA).
According to the Liturgy for the Ordination of Elders, elders of the church:
In the Reformed Church, we ordain women and men to three offices: the Minister of Word and Sacrament, the deacon and the elder. Ordination is the setting apart of the person, the recognizing and affirming of their call, and the consecrating and commissioning of them to special service of God and the Church.
The ordination service involves the taking of vows and answering of questions, and also the laying on of hands. We see this particular practice in scripture as certain individuals are ordained to leadership such as Joshua in Deuteronomy 34:9: "Joshua son of Nun was full of the spirit of wisdom, because Moses had laid his hands on him; and the Israelites obeyed him, doing as the Lord had commanded Moses."
RCA Pastor Matthew van Maastricht writes about the laying on of hands and ordination:
“Laying on of hands is the clearest, most significant ordination practice. Old as time, it connects us not only to our own communion but also to the people of God across space and time. And it has become collegial. It used to be that only the minister laid hands on those being ordained as elders or deacons. Newer liturgical revisions include invitation for laying on of hands by the great consistory, which means all ordained elders and deacons who have served or are serving on that church’s consistory. In some churches, a significant number of the congregation may come forward—connecting the ordinand to the shared ministry of all who have been called into the ordained service of Christ’s church.
“For ministerial ordinations, ministers and elders from the classis are invited forward. This communicates that the church is governed not by individuals but by the gathering of offices. One person does not stand in Christ’s stead. Rather, the generations of gathered offices and shared ministry represent Christ’s ministry.”