If you vote in advance at a polling station on September 10-13, you will have to show your ID as usual and then your name is struck from the voter list. If your name is struck from the voter list, you can't request a mail-in ballot.

The same thing happens when you request a mail-in ballot. Your name is struck from the voter list. If you show up at the polling station to vote in person after requesting a mail-in ballot, you will have to explain why your name is already struck out from the voter list. You can say that it was a mistake or that you never got the mail-in ballot, but you will have to vote with a provisional ballot, not the regular one. Then they will check if they got the mail-in ballot, which was requested by you, back. If they didn't, your provisional ballot will be counted.