Disabling a trusted realm prevents any cross-realm authentication from taking place. Configuration data and trusted users are not deleted from your realm. If you want to delete this data, you must delete the trusted realm. For instructions, see
Delete a Trusted Realm
You can still view a disabled trusted realm in the Security Console.
In the Security Console, click Administration > Trusted Realms > Manage Existing.
Use the search fields to find the trusted realm that you want to edit.
Select the trusted realm that you want to edit.
From the context menu, click Edit.
In the Trusted Realm Status field, select Disable Trusted Realm.