type

  TmyProc = procedure(DlgResult: TModalResult);

implementation

procedure RefreshApp(DlgResult: TModalResult);
begin
end;

procedure TForm1.Button12Click(Sender: TObject);
var
   mp: TMyProc;
begin
   mp:=RefreshApp;
   MessageDlg('Test Message','Test',mtWarning,[mbOk],mbOk,mp);
end;