delete Item and load another on the same ApplicationWindow

[RLocksley]

Hey,
I have this Application which shows an Item and on ButtonClick it loads another qml file.

My Question is how do I close/delete "rootItem" instead of only set

rootItem.visible = false

because I dont need it anymore after the Button is clicked.

ApplicationWindow  {
        id: mainWindow
        .....

        Item {
           id: rootItem
         .....
           Button {
               id: okButton
               text: "OK"
               onClicked: { coreApp.receiveOkButtonClick() }
           }
        }

       Connection{
            target: coreApp

            onLoadPage: {
               var component
               var connectionPage
               component = Qt.createComponent( "qrc:/Page.qml" )
               rootItem.visible = false
               connectionPage = component.createObject( mainWindow )
       
               }
        }
}