function mouse_event() 
{
  if (event_type == EVENT_CLICK) 
  {
    my.pan += 90;
    //your_ent.pan += 90;
  }
}

action sound_on_click()
{
  my.ENABLE_CLICK = ON; 
  //my.emask |= ENABLE_CLICK;
  my.event = mouse_event;
}