34 C.F.R.  §300.517.  Transfer of parental rights at age of majority.

(a) General. A State may provide that, when a student with a disability reaches the age of majority under State law that applies to all students (except for a student with a disability who has been determined to be incompetent under State law)--

(1)

(i) The public agency shall provide any notice required by this part to both the individual and the parents; and
(ii) All other rights accorded to parents under Part B of the Act transfer to the student; and

(2) All rights accorded to parents under Part B of the Act transfer to students who are incarcerated in an adult or juvenile, State or local 
correctional institution.
(3) Whenever a State transfers rights under this part pursuant to paragraph (a)(1) or (a)(2) of this section, the agency shall notify the 
individual and the parents of the transfer of rights.

(b) Special rule. If, under State law, a State has a mechanism to determine that a student with a disability, who has reached the age of majority under State law that applies to all children and has not been determined incompetent under State law, does not have the ability to provide informed consent with respect to his or her educational program, 
the State shall establish procedures for appointing the parent, or, if the parent is not available another appropriate individual, to represent the educational interests of the student throughout the student's eligibility under Part B of the Act.