if you can unweave at the toe where you ended, then you should be able to unravel the sock. If you cant find it, I'd snip somewhere that looks like the end row and unravel. You may have a few inches that get lost this way.
Or - what part of the sock do you want to re-knit? just the leg? just the foot?
Thank you for your response. I want frog them and reknit them on smaller needles.