NFL owners voted to increase rosters to 47 players and approved the conditional sale of the New England Patriots to Reebok International chairman Paul Fireman before adjourning their annual spring meeting.Representatives of the league's 28 teams also authorized NFL officials to renegotiate a five-year contract with the sporting goods company that has supplied the official game ball since 1941. In addition, the use of electronic whistles designed to improve the league's instant-replay system could begin as early as next season.