Senior Vice President John Ternus is reportedly seen as a potential chief as the tech giant prepares for “a broad changing of the guard” Apple is set to undergo a “broad changing of the guard” as the US tech giant plans for the eventual succession from CEO Tim Cook, Bloomberg has reported.   Cook has guided Apple’s expansion into new product categories since taking over as CEO in 2011, solidifying its position as one of the world’s dominant forces in consumer electronics and digital services.