splitting yarn(?)

[justsmi]

I'm not sure what you'd call it, but I want to "split" a six-ply yarn into a three-ply yarn. What would that be called and is there a relatively easy way to do it?

[G J]

I've never tried it for long pieces, but with short ones, it twists. I'd guess you'd end up with a very tangled mess, since the yarn is twisted around. Good luck!