Userform Excel Checkbox Code Not executing

Hi I am trying to get the following Macro to work when the checkbox on the userform is not selected. The macro works fine when the checkbox is selected. But when I unselect the checkbox it does not change the value of "E38" to ""

I am also looking for a way for the Checkbox to remain selected once I unload the userform

Private Sub CheckBox_AddBDetails_Click() If CheckBox_AddBDetails = True Then Worksheets("Schedule of Supports").Range("E38").Value = TextBox_Name.Value Else Worksheets("Schedule of Supports").Range("E38").Value = "" End If End Sub