uses comobj; 
 
var 
  xcl, wkb: OleVariant; 
 
procedure TForm1.Button2Click(Sender: TObject); 
var anz: integer; 
 
  function before(welche, vorwelche: integer): boolean; 
  begin 
    if (welche < 1) or (vorwelche > anz) then result := false 
    else begin 
      wkb.Sheets[welche].Move(wkb.Sheets[vorwelche]); 
      result := true; 
    end; 
  end; 
 
  function after(welche, hinterwelche: integer): boolean; 
  begin 
    if (welche < 1) or (hinterwelche > anz) then result := false 
    else begin 
      if hinterwelche < anz then 
        wkb.Sheets[welche].Move(wkb.Sheets[succ(hinterwelche)]) 
      else begin 
        wkb.Sheets[welche].Move(wkb.Sheets[hinterwelche]); 
        wkb.Sheets[hinterwelche].Move(wkb.Sheets[pred(hinterwelche)]); 
      end; 
      result := true; 
    end; 
  end; 
 
begin 
  xcl := createOleObject('Excel.Application'); 
  wkb := xcl.workbooks.add; 
  anz := wkb.Sheets.count; 
  xcl.visible := true; 
  if not after(1, 3) 
    then showmessage('Falsche Sheet-Zahl'); 
end; 
 
 
procedure TForm1.FormDestroy(Sender: TObject); 
begin 
  if not VarIsEmpty(xcl) then xcl.quit; 
end;