Many people in Ireland today are Catholic, with some practicing the religion more than others.
But in light of church controversies and declining faith, some seek to leave the church they were baptised into as a baby.
Michael Nugent, Chairperson of Atheist Ireland, joined Moncrieff to discuss the history of the practice and how people are leaving today.
According to Mr Nugent, there are three parts to getting properly removed from the Church.
"First of all, you have to internally leave, you just decide yourself to leave, then you have to manifest it outwardly in some way."
"Thirdly - this is the big kicker - is that an ecclesiastical authority had to agree with you."
A friend of Mr Nugent's left the Catholic Church in the 1980s after completing interviews "that convinced them that he was that he was sane and of sound mind".
"We can use this process for our purposes, to show that we don't want the church to be claiming us as members."
The changes made to allow people to leave cleanly not only had religious consequences.
In some countries, such as Germany and Austria, members of the Church must pay extra tax.
Some people wished to be exempt, for religious and financial reasons.
Mr Nugent said: "In practice, nobody knew what it meant and different diocese were implementing it differently and so in 2006 they came up with this formal process just to define it, to try and put some sort of regulation on it."
"Obviously we can leave in her own mind", said Mr Nugent.
However, after certain scandals in the Church came to light, he believes it was "cathartic" for some people to be able to leave in an official capacity.
"Each diocese just makes up their own mind what they're doing."
"They might put a record, they mightn't. They might talk to you, they mightn't."
"It's just like the rules of Quidditch. You know, they make up whatever they want."
Listen back to the full conversation here.
Main image shows someone giving out Holy Communion. Picture by: Sebastian Gollnow/dpa