1. From the "Admin" tab, click the "Roster" menu item on the left sidebar. From here you have two options to edit a user. You'll notice a pencil icon pop up next to elements you can edit directly in the roster page. Alternatively you can use the Edit button to update other elements.
3. If you choose to click Edit you'll be taken to the below page. There are a few important things to call out here. First, you can change a users role in this page. If you want to give someone else Admin privileges or take them away you can edit that here. It's also important to hit Save after you've made any changes so they are not lost.