Is there a program out there or way to change a characters appearance (and the appearance only)?

Some examples of what I mean are like changing the Assassin to look like Natalya (not a big change there really), The Amazon to Blood Raven or a Rouge, the Sorceress to Jamella, or even the Sorceress to the Assassin; something just changes their appearance but doesn't effect their skills or voice. Would something like this be possible?

There's no "program" to do it, you'd have to make the mod yourself.