Wiktionary
change over
vb. (context transitive idiomatic English) to convert to, to make a transition from one system to another
WordNet
Usage examples of "change over".
Nevertheless, a lot could change over four decades, and I couldn't dismiss the possibility that once upon a time the attorney had possessed a hearty appetite for crow.
We intend this constitution to be a flexible document subject to change over time in the light of experience and changing historical conditions, but assert here that we hope to establish a government that will forever uphold the following principles: the rule of law.