Rather than undoing this sock, I grabbed my crochet hook and made the necessary changes to the stitches at the back of the leg. It saves undoing lots and lots of rows, and most times it's successful. Note I said, most times.
From boring heel to one a little more interesting (and a little more work - but worth it). Note: the picture below includes several rounds of knitting after the trick with the crochet hook (which simply made some of the knit ribs purl and placed a knit rib at centre back to start the 'stem').