You can try to use a crochet hook to repair it the way you would a dropped stitch. Get to the point where the incorrect stitch is the first stitch on your left needle. Put your hook in the black stitch below where you want the white one to be, inserting it from the front. Then hook on to the top white strand running across the back and pull it through and put it on your left needle. Knit away!
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry