34 C.F.R. § 300.508
(a) General.
(b) Content of complaint. The due process complaint required in paragraph (a)(1) of this section must include—
(d) Sufficiency of complaint.
(3) A party may amend its due process complaint only if—
(e) LEA response to a due process complaint.
(1) If the LEA has not sent a prior written notice under § 300.503 to the parent regarding the subject matter contained in the parent's due process complaint, the LEA must, within 10 days of receiving the due process complaint, send to the parent a response that includes—
(f) Other party response to a due process complaint. Except as provided in paragraph (e) of this section, the party receiving a due process complaint must, within 10 days of receiving the due process complaint, send to the other party a response that specifically addresses the issues raised in the due process complaint.
(Authority: 20 U.S.C. 1415(b)(7), 1415(c)(2))