set (my,INVISIBLE);
reset( my, INVISIBLE);

..

set (my, FLAG1);
reset (my, FLAG1);
if (is(my,FLAG1)) do_something
if (!is(my,FLAG1)) do_something

..

ENTITY* the_light;
ENTITY* the_ent;
action TheLight(){
 the_light = me;
 the_light.lightrange = 200;
 ..
}
action TheEnt(){
 the_ent = me;
 ..
}

..

action / function(){
..
while (!the_ent) wait(1);
while (!the_light) wait(1);
var mytimevalue; //fex.
if (mytimevalue >= 100) { 
   reset (the_ent, VISIBLE); 
   reset (the_light, VISIBLE); //if visible model
   the_light.lightrange = 0;
   //reset(the_light, LIGHT);
..
}