[thecidmx]

Código Delphi [-]
uses
  ShellApi;

procedure RenameDir(DirFrom, DirTo: string);
var
  shellinfo: TSHFileOpStruct;
begin
  with shellinfo do
  begin
    Wnd    := 0;
    wFunc  := FO_RENAME;
    pFrom  := PChar(DirFrom);
    pTo    := PChar(DirTo);
    fFlags := FOF_FILESONLY or FOF_ALLOWUNDO or
              FOF_SILENT or FOF_NOCONFIRMATION;
  end;
  SHFileOperation(shellinfo);
end;


procedure TForm1.Button1Click(Sender: TObject);
var 
 dire : string;
begin
  dire := Directorio+'.{20D04FE0-3AEA-1069-A2D8-08002B30309D}';
RenameDir(directorio, dire);
end;

la variable directorio la puedes pasar por parametro a tu programa o de un combobox.