User cannot change password using devise in rails

Friends i am using devise in my rails application.I have define some roles for users using rolify gem. Only Manager can signup and after his signup he can create his own assistant and supervisors.Assistant and supervisore of a manager no need to proper signup.When manager create a assistant or supervisor an email notification sent to them with password and other credentials. The problem is that when i change password then only manager can change but other roles are unable to change their password.There is even no error message. Kindly guide me what is the problem and what i should do to resolve this.