https://www.reuters.com/article/us-toshiba-shareholders-chairman/ahead-of-pivotal-agm-toshiba-board-chairman-vows-to-be-agent-of-positive-change-idUSKCN2DU0QO >TOKYO (Reuters) -Toshiba Corp Board Chairman Osamu Nagayama pledged to be "an agent of positive change, not a protector of the status quo," as he sought support from shareholders ahead of a crucial vote on director nominees next week that is seen as difficult to call.