A few years ago I forgot to sign my mail in ballot and the local election board contacted me and let me come down and correct it so it could be counted. They did not just throw my vote away. BUT, this was before our state election board was run by Maga sycophants who look for any excuse to cheat.
This is called ballot curing and unfortunately, ballot curing looks different in all 67 counties in PA. Some do it, some don't. Wouldn't it be great if the legislature ensured that all voters have the ability to ensure their votes are properly cast and counted? Yeah, they can't even do a budget.
Pesky "may" not "shall" in writing laws