Sub SaveToUTF8(sSourceFile As String)

    Dim MyDoc As Document

    Dim sTargetFile$, i&

    If Dir(sSourceFile) = "" Then MsgBox sSourceFile & " not exists": Exit Sub

    i = InStrRev(sSourceFile, ".")

    sTargetFile = Left(sSourceFile, i - 1) & "_ToUtf8" & Right(sSourceFile, Len(sSourceFile) - i + 1)

    Set MyDoc = Documents.Open(FileName:=sSourceFile, ConfirmConversions:=False, AddToRecentFiles:=False, _

        Revert:=False, Format:=0, Visible:=False)

    With MyDoc

        If .OpenEncoding = 65001 Then MsgBox "This is a UTF8-encoded text file!": .Close: Exit Sub

        .SaveAs FileName:=sTargetFile, fileformat:=7, Encoding:=65001

        .Close

    End With

End Sub