Barb in Louisiana

It should work fine. Try it by ripping out around the corner, then pin baste the new seam to the corner where you would want it to be. Redo the miter and see if it works. I think it will. Wish I had a quilt ready to bind, because I could tell you really quickly.

Edited to add: Worst case scenario, you might have to rip further down the side, cut the binding and rejoin it, then complete with the new seam allowance. That would certainly be better than having to rip all the binding off.