My mom owns a co op.......in her will she has stated that the co op be left to both me and my sister. Mom is getting on in age and my sister wants to live with her. According to the board her name has to be on the certificate of shares. If my mom adds her to the certificate does she by law now become an owner of the co op. Can she be added without being an owner of any shares? If added will this now take away my 50% ownership if my mom should pass away. Does she get the co op? How can we resolve this problem.