I'm doing something similar with cuffs that are too loose. It should work.
Something that surprised me, but shouldn't have: when you start to undo from the cast-on edge, you can't just rip as you would if you were undoing from the cast-off. You have to undo every single stitch and pull the yarn through. Very tedious if you're looking at a lot of rows or a lot of stitches.
I found it better to snip a stitch right below my target row and pull the stitches out from the top. Then you're left with a detached cuff, which you can rip down if you want to reuse the yarn or you can discard if you're going to knit the cuff with new yarn.