You can remove a section of STD quilting quite easily. Give yourself "tails" at the end of both sections and knot and bury the thread tails. Start stitching in the same hole that you buried the thread ends and STD up to the start of the next section. You do have to be careful when you are getting close to rejoin the stitching to make sure the top or bottom haven't walked or you might get a pucker where you rejoin. So a chance of a pucker or a "kiss" as some call them or wonky STD. It's up to you.