When a partner is created in the system a reseller account is created at the same time. To be able to remove the partner we will have to change the reseller account.
Navigate to the Detail tab and the Partner Section. Click Edit.
Select the empty alternative in the dropdown menu and click Confirm. The account is not marked like a reseller account any longer and can now be removed. (Important: the account can´t be removed if the account has transactions)
Navigate to the account overview again. Click the action menu to remove the account.
To remove the Partner, navigate to User Management > Partners. Click the action menu and select Remove User.
Navigate to User Management > Disabled to find the removed user.