1) One does not convert to atheism, one simply reconverts from religion. Atheism is not a religion.
2) The only thing that atheism is marked by is the lack of belief in any gods, thus if you don't believe in any gods, you're an atheist already. No external signs. professions or rituals are required.
Atheism should be arrived upon self-realization, not for the benefit of conforming to others.
No rituals or anything other than education and a decent intellect is required!
Acceptance of a supernatural claim tends to promote cooperative social relationships. This communication demonstrates a willingness to accept, without skepticism, the influence of the speaker in a way similar to a child's acceptance of the influence of a parent. By encouraging this kind of behavior where the most intense social relationships occur it facilitates the lack of skepticism and deters more open minded thinking.
They are christian, Muslim or the other religions depending where they were born simply because they were indoctrinated by their parents as very young children. They will go on to indoctrinate their own children and those will go on to indoctrinate their grandchildren!
Atheists have the intellect to see through the conditioning and escape into the real world!
Agnostics have the intellect to see through the conditioning but lack the courage to throw of the conditioning entirely.
Sadly Christians are still held firmly prisoner by the self perpetuating brainwashing!
Sacrifice a screaming Babb to an idol of Darwin, paint yourself in it's fresh blood and chant "Dawkins, Dawkins, EVIL-loot ion".
I am being deliberately obtuse, do not do this or you will end up in a nasty cell somewhere with a demented redneck skinhead named Bubba who will make you into his woman!
No rituals.....jolly....no celebrations....jolly,money saved. No functions....jolly...again money saved. The only work bashing the religion and god. That is easy. Any tick and tom can do. Nearly all atheists are like tick and tom only.