SNAG Wrote: "So that you can turn it around so that the previously-folded piece is now on the tread , and the worn area is now folded under . Carefully pull the tacks/staples that hold the carpet to the riser on one step , confirm that there is enough to reverse it , should be pretty straight-forward . Rent or borrow a knee kicker if you don't own one - and some knee pads . You'll probably find the sides tacked too , unless the carpet touches wall/trim on both sides . Probably a good idea to replace the pad as you go , it plays an important part in how fast the carpet wears".
Thanks for the words, I had not even considered there might be a pad below the stair tread portion of the carpet. I'll make sure to have a source of padding available before I start a major tear-out.