If you want to promote or demote your workspace members, go here. Alternatively, click on the name of your workspace (upper-left corner of the screen) → Manage Members:
There, click the little arrow next to the member you want to promote or demote and choose the desired role. You can read more about the different types of roles here.
- From Editor to Viewer: click the "Remove from workspace editors" button.
- From Viewer to Editor: click the "Add to workspace editors" button.
- Add as Admin: click the "Add to workspace admins" button.
- Remove from Admins: click the "Remove from workspace admins" button.
Please note that only administrators can change workspace member roles.