They'd probably just say ok and keep scheduling you the same shifts in pfresh where you'd do the same work with similar expectations for less pay 😛. Granted you could fix that somewhat by altering your availability.
I do market shifts personally where I'm expected to do anything a PA would do. Opening routines, SDAs, cleaning routines, orders, the whole 9 yards. Bargain for them because I'm an N07 instead of N09.
Our CTL just quit or was performanced out (not sure, didn't get the full story), so now the PA is running the department. I can't complain, gets me a lot of hours over there, ~40 out of 75 the next couple weeks. We're getting coverage when neither of us is available by utilizing an electronics TM and a merchandising brand TM from softlines, neither of whom have ever worked there. They're basically just zoning, either myself or the PA is opening every morning. So yeah this might be where you find yourself if you ask to step down, a PA making less money.