Whenever this creature attacks, add {R} at the beginning of your next main phase this turn.
{3}{R}{R}: Transform this creature.
If Conduit of Storms attacks and you transform it into Conduit of Emrakul in response, you’ll add {R}, not {C}{C} and not {C}{C}{R}.
You’ll add mana at the beginning of the next main phase whether or not Conduit of Storms (or Conduit of Emrakul) is still on the battlefield.