What will we need to do regarding any provisions in the stimulus bill that have a retroactive affect on 2020 taxes already paid, such as the unemployment insurance taxes?

There is language in the latest stimulus bill that provides relief from unemployment taxes already paid, I believe up to a total of $10,200. This will probably require an amended return, but then will they also be reimbursing the taxes already paid and sending out a check for any money owed back to us? How does this typically work?