When I voted in the recent primary, I wanted to change one of my votes that showed on the "review screen". I looked for a way to navigate back to the "voting screen" but I could not find one. I tried changing the vote on the review screen but it would not change. I finally noticed a "help button" and used it to call up some instructions. (You know, if all else fails, read the instructions.) I learned that to change my mistaken vote I would have to touch the incorrect vote to turn it off (like a toggle) so that I could then vote for the other choice.
I managed to figure it out. After all, I have decades of experience with computer technology. But, I can see how someone who has never used a computer, like many who vote in certain Florida precincts, could have problems. Not to mention poll workers who have no technical knowledge or skills.