Through the user interface The Raiser's Edge automatically convertes the constructed Addressee value into a string.  This must be done manually through the API by saving the field to a temporary string and then replacing the Primary Addressee field with that same string.  The follow code demonstrates this functionality:

Public Sub TestEditable()
    Dim oConst As CRecord
   
    Dim oConsts As CRecords
    Set oConsts = New CRecords
    oConsts.Init REApplication.SessionContext
   
    Dim sAddr As String
   
    For Each oConst In oConsts
        Debug.Print oConst.Fields(RECORDS_fld_FULL_NAME)
        If oConst.Fields(RECORDS_fld_PRIMARY_ADDRESSEE_EDIT) = False Then
            sAddr = oConst.Fields(RECORDS_fld_PRIMARY_ADDRESSEE)
            On Error Resume Next
            oConst.Fields(RECORDS_fld_PRIMARY_ADDRESSEE) = sAddr
            oConst.Fields(RECORDS_fld_PRIMARY_ADDRESSEE_EDIT) = True
            oConst.Save
            If Err.Number <> 0 And oConst.Fields(RECORDS_fld_PRIMARY_ADDRESSEE) <> "" Then
                Debug.Print Err.Description
                oConst.Closedown
                Set oConst = Nothing
                Exit For
            End If
        End If
       
        oConst.Closedown
        Set oConst = Nothing
       
    Next oConst
   
    oConsts.Closedown
    Set oConsts = Nothing

End Sub

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