Как программно изменить текущий порт принтера

uses Printers;

{$IFNDEF WIN32}
const MAX_PATH = 144;
{$ENDIF}

procedure TForm1.Button1Click(Sender: TObject);
var
  pDevice: pChar;
  pDriver: pChar;
  pPort: pChar;
  hDMode: THandle;
  PDMode: PDEVMODE;
begin
  if PrintDialog1.Execute then
  begin
    GetMem(pDevice, cchDeviceName);
    GetMem(pDriver, MAX_PATH);
    GetMem(pPort, MAX_PATH);
    Printer.GetPrinter(pDevice, pDriver, pPort, hDMode);
    Printer.SetPrinter(pDevice, PDriver, 'FILE:', hDMode);
    FreeMem(pDevice, cchDeviceName);
    FreeMem(pDriver, MAX_PATH);
    FreeMem(pPort, MAX_PATH);
    Printer.BeginDoc;
    Printer.Canvas.TextOut(100, 100, 'Delphi World Is Wonderful!');
    Printer.EndDoc;
  end;
end;