If you need to remove an Administrator from ESS follow the steps below:
Log into ESS as an Administrator user.
Go to Teams and select the team you need to remove the Administrator from, you may have multiple Administrator teams.
Click on the ellipsis (three dots) button for the user and select Remove from Team.
Confirm removing the member from the team.
You can then go into that team members profile select Teams & Roles and check that they no longer belong to the Administrator team and also check if you need to remove them from any other teams.