You must have administrator authority to remove a user from the organization. To do so, start by clicking on the current organization.
Then click "Administration" > "Users" in the left menu.
Next, click on the icon with the three dots (···) next to the user you want to remove from the organization and select the "Remove" option.
Confirm the removal by clicking "Remove".
The user is then removed from the organization. All of the organization's previous users are listed under the "Previous users" tab.