The ballot does NOT have your name or any other identifying information. That is why we call it “secret” voting system. When I mailed my absentee ballot, only place where my name appears was the outside envelope.
Once they remove ballot sheet from the outside envelope, there is no way to know which ballot paper sheet was yours. So how is your old vote removed?
The news has reported that there i-s a bar code on those balllots in the states that allow vote changing
My take is that the votes can be changed as per the democrat fraud unit wants
when the ballot is removed it is checked off the list the list of your vote.