AT&T acquired HBO’s parent company in June. It was part of an $85 billion deal between AT&T and Time Warner. Now AT&T is starting to make major changes. It’s consolidating divisions and putting a new executive in place -- Robert Greenblatt -- to oversee entertainment, including HBO. That explains the departure of Richard Plepler, who was HBO’s CEO since 2013. Plepler green lit hit shows like “Game of Thrones,” “Girls,” and “Veep.” He announced last week that he’s resigning.