1. Go to Teams page from the sidebar menu
2. Click on three dots far right from the name of the team you wish to change productivity label for
3. Select review usage
Here you can review all labeled apps and websites or categories, and apply different productivity labels to them
Note: To change already reviewed app or website's productivity label you can either go to Teams page and select the desired team as described above, or select change existing labels when you click on Review Productivity button.
Another way to reach to already labeled items is directly from specific team's page by clicking on review productivity buton found there next to the name of the team.