I have an assigned voting location, but there are several in my district that are all “valid”, and I was just assigned the one closest to my house. If I were to be confused and go to a valid location I wasn’t assigned to, I’m still in the ledger. Since I’m attempting to vote in the correct district, they don’t really have grounds to turn me away.

If I were in the wrong district, I’m still allowed to cast a provisional ballot, which lets you vote but they sort it out later.

You can also vote absentee and then also in person and not disclose that you need to invalidate the absent vote. Here that’s automatic, but in some places it’s a crime.

You’re also allowed to go to a clerks office, which has the equipment to print any ballot and handle it correctly.