The girls and I had errands in town, and I stopped by the polls on the way home. We're in a rural area, and there was only one woman in line ahead of me. I asked the woman behind the table if it would be alright for me to take the girls into the booth, to explain things to them. She sighed, and replied, "I guess so... as long as they don't touch anything."
So, our turn came, and we ducked behind the screen. I explained to the girls that you can push a button, and if you make a mistake, you can change it. UNTIL you push the red button that says CAST YOUR VOTE, that is. And just for good measure, I pressed the write in button for president. And wouldn't you know that it WOULD NOT let me change that particular button. And so, after talking with the ladies who were running the booth, and getting very frustrated because they told me that I needed to just push the big red button, and that I actually would not get to vote for anyone because I had been stupid and pushed the wrong button, I decided to write in my choice even though they were already on the ballot.
Lesson learned. Apparently, you CAN change your mind, unless you push the write-in button. I'll remember that next time.