As a man who changed from homosexuality through my study of Aesthetic Realism and someone new to this talk page, I am perplexed by the objection to the simple, clear, entirely grammatical phrase, "changed from homosexuality."
To quote one source, Websters Dictionary, the first definition of the intransitive verb "change" is "to become different." This describes percisely what occurred in my life. I was homosexual; I became heterosexual. If this isn't appropriate language and readily understandable to the vast majority of English speaking people over the age of (conservatively) 12, I don't know what is.