Originally Posted by thimblebug6000
Just pick out the stitching that's holding the block in, and then about an inch on the surrounding seams, cut your new block & insert it, by stitching the seams back together, try to follow the same order of stitching the seams as they were originally. (that's what I've done in the past)
I've done this a few times as well, when I found I had sewn the block in wrong or found a hole. It's very doable.