GitGuardian allows you to be member of several workspaces. Thus, your email address can be associated to multiple workspaces.
However, GitGuardian allows you to only create only one workspace yourself. In order to be member of other workspaces, you must receive an invitation. You can be a member of at most 5 workspaces.
If you are member of several workspaces and you want to switch the workspace you are currently viewing, click on the first tab of the sidebar and then select the workspace to switch to.