To edit organization settings, select its node in the navigation pane and click Edit Org on the toolbar, or use the shortcut menu command. Then follow the steps of the wizard.
Consider that you can change Office 365 organization type only to the Hybrid type but not to the On-premises type.
Similarly, you can change On-premises organization type to the Hybrid type, not to the Office 365 type.
To remove an organization from the scope, select it in the navigation pane and click Remove Org on the toolbar, or use the Remove organization command from the shortcut menu.