ABSTRACT - Sprint Corp agrees to several changes in governance, including how its directors are chosen and when its executives can sell shares; changes are part of settlement of lawsuits filed by Sprint shareholders over company's unusual treatment of executive stock options during scuttled mergers; Sprint agrees to pay $50 million to shareholders to settle one suit, class action filed in federal court in Kansas City, Kan; says most of that amount will be covered by insurance; Robert Monks, shareholder advocate who advised plaintiffs in second suit, says Sprint agrees to changes that would make its board more independent and more accountable; Amalgamated Bank, which is owned by labor unions and holds about 600,000 shares of Sprint, filed suit in Missouri; Sprint's directors will stand for election every year starting next year, instead of every three years; two-thirds of them must meet tougher standard of independence and one independent director will serve as lead director (M) In a legal settlement that may signal that the battleground for corporate reform has shifted to the courts, the Sprint Corporation said yesterday that it had agreed to several changes in governance, including how its directors are chosen and when its executives can sell shares.