If you have been away from Brown for longer than one year and have not successfully  requested that the leave be extended, you are no longer considered actively enrolled in a degree program, and must reapply to be reinstated. In order to initiate this process, write a letter to the Associate Dean of the Graduate School, with a copy to the Director of Graduate Studies. Either the Director of Graduate Studies or a representative will contact you to let you know what steps you must take at that time.