With Lite-C, you can do :

function main()
{ // Here 2 panels and changing visible states
set(SplashScreen,SHOW); // or SplashScreen.flags |= SHOW ;

wait(-10);

reset(SplashScreen,SHOW); // or SplashScreen.flags &= ~SHOW ;
// or toggle( SplashScreen, SHOW) ;

// And finally
set(MainMenu,SHOW); // or MainMenu.flags |= SHOW ;
// or also toggle(MainMenu,SHOW); if mainmenu was not visible
}

regards.