User blog comment:X-Machinist-X/Dishonored random stuff/@comment-26438896-20160209225936/@comment-26438896-20160210195105

It's pretty complex to explain, also because each model may (not at all) have different facial rig/bones and, if you want to swap heads, maybe the facial manipulation of one may not work on the another, so...

if you want to use somebody's head on another's body, you'd better put also its facial bones - I never tried it, but I'll do when I learn the secrets of making armatures and models. I may also be wrong.