Let me see if I can make this explanation as clear and short as possible. I'm working on a sweater. There's a section of short rows that makes a rounded edge from the back of the sweater up the front. I've got it all done, shoulders sewn together, tried it on for fun, and I realize one side sorta pooks out a little more than it should. On looking more closely at this one side I realize I did 6 repeats of the short rows instead of 5. As luck would have it, I actually ran out of yarn at almost the end of one repeat. Is there any way for me to rip out that extra repeat? But how will I get the two pieces together again? I won't be working over straight stockinette - it's a cabled pattern and a garter stitch edge. This unfortunate mistake happened in the middle of the piece, so my only other options, it seems, are to frog back to the mistake - which would really bum me out - or grow larger hips - which would really bum me out too.
I don't think that's going to be an easy mistake to fix. You could cut and then put both sides on needles and graft it, but it may always show along that grafting line. Plus it may not work well since it's short rows. Personally I think I'd call it lesson learned and frog back.
When asking questions ALWAYS post the name and a link for the pattern if you have it.