28 CFR 76.9 - Responsive pleading
(a) Time for answer. A respondent shall file and serve on the United States Attorney having jurisdiction over the matter an answer within thirty (30) days after the service of a complaint.
(b) Default. Failure of the respondent to file and serve an answer within the time provided shall be deemed to constitute a waiver of his or her right to appear and contest the allegations of the complaint. In such cases, the Judge may enter a judgment by default.
(c) Answer. Any respondent contesting any material fact alleged in a complaint, or contending that he or she is entitled to judgment as a matter of law, shall file an answer in writing.
(1) The answer shall include a statement of the facts supporting each affirmative defense.
(2) The answer shall include a statement that the respondent admits, denies, does not have and is unable to obtain sufficient information to admit or deny each allegation, or that an answer to the allegation is protected by a privilege, including the privilege against self-incrimination.
(3) A statement of lack of information or a statement that the answer to the allegation is privileged shall have the effect of a denial.
(4) Any allegation not denied shall be deemed to be admitted.
(e) Amendments and supplemental pleadings. If it will facilitate resolution of the controversy, the Judge may, upon such conditions as are necessary to avoid prejudicing the public interest and the rights of the parties, allow appropriate amendments to complaints and other pleadings at any time prior to the issuance of the Judge's order based on the complaint. When issues not raised by the pleadings are reasonably within the scope of the original complaint and are tried by express or implied consent of the parties, they shall be treated in all respects as if they had been raised in the pleadings, and such amendments may be made as necessary to make the pleadings conform to the evidence. The Judge may, upon reasonable notice and such terms as are just, permit supplemental pleadings setting forth transactions, occurrences, or events which have happened or new law promulgated since the date of the pleadings and which are relevant to any of the issues involved.