Mary Bruce has details on Vice Pres. Kamala Harris' first sit-down interview since becoming the Democratic nominee, defending her changing policy positions to CNN and saying her "values have not changed"; Erielle Reshef reports as Massachusetts health officials confirm a second case of the mosquito-borne virus EEE, marking the sixth known case in the U.S.; Ian Pannell has the latest on the American-made F-16 fighter jet in Ukraine that crashed while trying to intercept a Russian missile strike, killing its pilot; and more on tonight's broadcast of World News Tonight with David Muir.