Michaela Martens will replace Stephanie Blythe in the San Francisco Opera’s upcoming production of “Elektra.” Martens will appear in the role of Klytemnestra in a new staging by Keith Warner, which starts on Sept. 9, 2017. She is set to take on Klytemnestra with Houston Grand Opera in January 2018 as well. Martens’ San Francisco Opera debut came in 2015 {…}