1. (Above) The increase SHOULD HAVE BEEN MADE between the brown stitch and the purple stitch, but instead the increase (red) was MISTAKENLY MADE between the purple stitch and the blue stitch.
2. (Above) Slip the needles through the work until you have your needles poised over the error (there is more information about slipping in the last note of this post). Between your needles, drop down a runner, turning all the stitches ABOVE the red and purple stitches into the rungs of a ladder. This will free the increase to be moved. Locate the "tail" of yarn (arrow) in the location where the increase should have been in the first place.
3. (Above) The tail marked with an arrow in illustration 2 has been pulled up, and the excess yarn distributed to form a loop where the increase should have been made in the first place. In other words, the increase (red stitch) has been moved from one side of the purple stitch to the other.
4. (Above) Hook the ladder rung above the newly-repositioned red stitch through that stitch, then continue hooking up each ladder rung in this column, turning each rung back into a stitch in its own right. Finish by placing the last stitch in the column on your left needle. (Although this is not illustrated, the easiest way to perform the hooking operation is with a crochet hook.)
5. (Above) Lastly, hook the ladder rung above the purple stitch through, then continue hooking up each ladder rung in this column, turning each rung back into a stitch. Finish by placing the last stitch in the column on your right needle. Your increase has been moved to the correct spot.
The increase illustrated above is a twisted loop increase (also called "make 1" or "M1"). However, this trick works with any kind of increase--just release the stitches in the increase column down far enough until the loop of the increase itself is freed. Once you've relocated the excess yarn for the increase by pulling the excess yarn through to the stitch-tail located where the increase should have been, you make your new increase using the exact same method (twisted loop, knitting into the stitch below, whatever) as you made all your other increases.
As stated in the post on moving decreases--the illustrations above are not to scale--even one released stitch makes a ladder too wide to illustrate properly--the illustration would go off the page. Don't be worried, though, the ladder you create is supposed to be wider than the illustration--that just shows you're doing it right.
Finally, the illustrations show the needles having been slipped through the fabric to the correct spot. The last note in the decrease post explains why.
--TECHknitter
(You have been reading TECHknitting on: moving increases wrongly positioned in the row below)