var
  FWordApp: OleVariant;

  FWordApp := CreateOleObject('Word.Application');

procedure ProcessOneFile(const FileName: TFileName);
var
  _Name: WideString;
begin
  if VarIsEmpty(FWordApp) or VarIsNull(FWordApp) then Exit;
  _Name := FileName;
  try
    FWordApp.Documents.Open(_Name);
    _Name := copy(FileName, 1, Length(FileName) - 3) + 'doc';
    try
      FWordApp.ActiveDocument.SaveAs(_Name);
    except
      on E: Exception do begin
        showmessage(e.Message);
      end;
    end;
    FWordApp.ActiveDocument.Close;
  finally
    _Name := '';
  end;
end;