How to unfreeze an attributes?

I can use this to freeze an attribute In Version EB 2019 6.8.2)

Public Sub test()

    Dim obj As ObjectItem

    Set obj = Application.Selection(1)

    Dim attr As Aucotec.Attribute

    Set attr = obj.Attributes.ItemByID(aucAttrComment)

    attr.Frozen = True

    obj.Store 

    

End Sub

But unfreeze is not successfull ,When obj store .How can I unfreeze an attribute.

Public Sub test()

    Dim obj As ObjectItem

    Set obj = Application.Selection(1)

    Dim attr As Aucotec.Attribute

    Set attr = obj.Attributes.ItemByID(aucAttrComment)

    attr.Frozen = False

    obj.Store

    

End Sub