I've already undone the waist stays and seams (my, I was careful when I repaired this in 1987, and while I had a billion stitches to undo, it was worth it). I am never going to have a 26 waist again, so I need to find about five or more inches of extra fabric somewhere to make it work. I get four of those out of the darts I'm removing from the bodice, but I am going to figure out a center bodice insert to make up the bulk of that (I'm not quite that flat chested, and I don't want to turn a graceful triangular shape into a square). Some gusset work for the sleeves (yeah, those arms ain't going back there either) and I should be in business.
I will have to move the skirt up to get more waist width. I had a big back porch then, and I have it still, so that's not quite a tragedy. I want to wear this, I missed it. The blessing of mending: I can make it work for me again.