I suppose I should clarify my blog name since there is the potential for significant misunderstanding (although probably not if you actually read many of my blogs, lol).
Usually, when a person changes beliefs---and particularly in the case of religious beliefs---he or she is said to have been converted to the new system. Unfortunately, Islam completely inappropriately describes those converted to Islam as being reverted. (To revert is to change back, or return, to a previous state.) The reason they do this is because they claim that everyone is born a Muslim.
I vehemently disagree with this absurd (and self-evidently false) assertion. No baby "believes" anything. It is no more appropriate to describe a baby as a Christian or Muslim than as a Capitalist or Marxist. It is simply too young and inexperienced to form a belief one way or the other.
Atheism is the "absence of belief in the existence of God or gods", or "disbelief in the existence of God or gods". The former exactly describes the state of a newborn on the topic of god(s). Newborns are atheists.
I was an atheist at birth. I subsequently spent many years believing Christianity. Through honest, rational examination of the available evidence, I eventually returned to atheism (this time leaning more toward the latter definition).
I am reverted.