Not the best picture but it tells a story.
Last night I decided I really wanted to wear this dress today but the facing needed some repair (really wasn't the best fabric choice for facing). I also have wanted pockets on this.
So...with some help from my trusty assistants, I folded the dress in half so that the side seams were in the middle, placed the facing pattern just below the arm hole on the seam line, cut out a new arm hole and neckline, flipped the pattern piece upside down and over to the other side, cut the rest of the neckline and the second arm hole. I had to cut a little more out of the neckline to get it over my head and to smooth things out.
I then sewed the shoulder seams (french seams) and finished the neckline and arm holes with a rolled hem, which is the most common way I finish necklines, armholes and hems. This is the proper way to do a rolled hem. I skip the ironing and just roll the hem, finger press, and stitch once.
I'll use the fabric I cut off to make a pocket later, but for today it's ready to go!
P.S.
The side seams are now center seams.