S.C. Code Ann. § 44-20-440

Subject to the availability of suitable services and programs and subject to the provisions of "Requirement for Admission to Services", "Order in which Person May be Admitted", and "Final Authority over Eligibility", the office director or his designee may admit a client to the services of the office upon the written request of the parents of the person with intellectual disability, a related disability, head injury, or spinal cord injury, a parent with legal custody, spouse, lawful custodian or legal guardian, or the person with intellectual disability, a related disability, head injury, or spinal cord injury seeking to be admitted to the office's services if the person is twenty-one years of age or over and competent to make the decision. The office shall prescribe the form of the application for services.