Randall Stephenson, the longtime chief executive officer of AT&T, is stepping down. Stephenson will be succeeded by AT&T Chief Operating Officer John Stankey, who will take over the role on July 1.

Stephenson has served as AT&T’s CEO for more than 13 years and oversaw the massive acquisitions of CNN parent company Time Warner (now known as WarnerMedia) and satellite TV provider DirecTV.

AT&T said Friday that Stephenson will remain the company’s executive chairman until January 21 “to ensure a smooth leadership transition.” Stankey will join the board on June 1.