Time Warner Inc.'s Turner Broadcasting System Inc. CEO John Martin is exiting the company, Deadline reported, citing a staff memo from John Stankey, CEO of AT&T's media business.

Upon Martin's departure, Turner President David Levy, Turner International Inc. President Gerhard Zeiler and CNN Worldwide President Jeff Zucker will start reporting to Stankey.

According to Stankey's memo, the daily operations of Home Box Office Inc., Turner and Warner Bros. Entertainment Inc. "will see little change," but many redundant corporate roles between the companies at the headquarters and holding company level will be removed in the coming months.

AT&T Inc. is also renaming its newly acquired Time Warner subsidiary to WarnerMedia, following the recent completion of AT&T's $85.4 billion acquisition of Time Warner.

According to Stankey, changing the unit's name to WarnerMedia is largely a naming convention as the company seeks to eliminate the confusion among the company's stakeholders "who never learned to distinguish between Time Warner, the media company, and Time Warner, the former cable company."

He added that the important customer-facing brands such as HBO, CNN, Warner Bros. and TNT (US) will remain unchanged.