convert from (something)
1. To leave one religion in order to follow another. I converted from Catholicism to Judaism in preparation for my wedding.
2. To change or shift from one thing into another. Did she really convert from that shy kid into a punk rock singer?
convert from something (into something)
and convert (from something) (in)to somethingto change from one thing into another. We converted from oil to natural gas to heat our house. I had hoped he would convert from an impatient youth into a relaxed gentleman. He did not.