ABC Evening News Anchor Diane Sawyer Replaced
Diane Sawyer is to be replaced as ABC's evening news anchor, becoming the second top female journalist to step down at the US network in as many months.
Sawyer will pass the mantle of World News presenter to David Muir, 40, while she focuses on interviews and specials, said the network.
The 68-year-old has held the top news job for nearly five years and has been with ABC since 1989.
The Disney-owned network said George Stephanopoulos, host of Good Morning America, would also assume a new role - as chief anchor for live news events.
ABC News President James Goldston announced the reshuffle on Wednesday.
"Diane is one of the giants of modern journalism, and we can't wait to see where she'll lead us next," he said.
Rumours had been circulating for some time that Kentucky-born Sawyer, a former aide to President Richard Nixon, would step aside.
Her exit comes a month after World News scored a rare win over its leading rival, NBC Nightly News, among viewers in the coveted 25-54 age group.
Analysts noted that her departure leaves three white men anchoring the nightly news: Muir on ABC, NBC with Brian Williams and CBS with Scott Pelley.
Sawyer is the second high-profile ABC female presenter to step aside in as many months following May's retirement of Barbara Walters.