Diane Sawyer Stepping Down at ABC's World News To be replaced by David Muir By Newser Editors and Wire Services Posted Jun 25, 2014 10:18 AM CDT 26 comments Comments In this March 24, 2012 photo, Diane Sawyer attends Aretha Franklin's seventieth birthday party in New York. (Charles Sykes) (Newser) – Diane Sawyer is stepping down as anchor of ABC's World News in September after nearly five years in the job, to be replaced by her regular substitute, David Muir. The network also said today that George Stephanopoulos will add the role of chief anchor for live news events to his current jobs as Good Morning America co-host and host of the Sunday-morning This Week political show. The exit of Sawyer, 68, is not unexpected. She will remain at ABC News to concentrate on big interviews and prime-time specials. World News was a steady second to Brian Williams at NBC during her tenure, although the ABC broadcast has made gains among younger viewers. Muir, 40, has been groomed for the job. He steps in when Sawyer is away, and traveled to China to report with her in 2010. He has a high profile on World News with his regular "Made in America" series of stories from around the country. As chief anchor of live news events, Stephanopoulos takes over a role traditionally held by the evening news anchor at most network news divisions. Evening news anchor was once considered the top job at a broadcast news division, but ABC does not want to disrupt the team of Stephanopoulos and Robin Roberts that has led the network to the top in the lucrative morning market. The evening news switch will take place on Sept. 2, says the president of ABC News.