I would suggest that the change from either atheism to theism, or visa versa comes not from new evidence, but a re-interpretation of the evidence at hand.
Probably the funniest thing I hear is the phrase "There is no evidence". There is a LOT of evidence all around us. The difference comes not from the existence of the evidence, but rather our interpretation of that evidence.
I sort of agree with that, but I don't know if you'll agree my take on it.
I've been an atheist for less than two years. (It'll be two years in November.) But I was Greek Orthodox for twenty years, and Eastern Christian theology is much more apophatic than Western Christian theology. For many years, I've seen theology as provisional and metaphorical, and "God" as a sort of metaphor for something ineffable. Admittedly, I probably went farther in this way of thinking than most Eastern Christians.
So it wasn't as great a leap for me to go from theism to atheism as it would be for a lot of people. However, it would be a great leap for me to go back, because I've come to see the whole god-metaphor as something harmful and destructive, and dogma as something almost infinitely more harmful and destructive than theism itself.
My first husband believed he was abducted by aliens multiple times. (Yeah, my life has been more interesting than I would always have liked.) He was very offended that I didn't "believe" him. I tried to explain, I do believe you. I believe you're having these experiences, but I think these experiences are psychological, not factual. Well, as you can imagine, that was never good enough. He believed he was having factual experiences, and I could never believe the phenomena he was experiencing were factual. The things he adduced as evidence never seemed like evidence to me at all.
I look at God pretty much that way. When theists tell me they experience god, I believe they're having experiences, but I don't believe their experiences are factual. I believe they're making myths from psychological experiences. I can understand that. I understand having a sense of wonder; I understand the impulse to worship. But I can't see my way clear to believe what theists believe about it.
As for revelation and dogma, I don't believe they have any value. I think they're very harmful. When you tell people that they
must factualize other people's subjective interpretations of their (the other people's) psychological experiences, that's really pretty crazy.