49 C.F.R. § 209.307 – Reply.

(a) Within 30 days after receipt of the notice of proposed disqualification issued under § 209.305, the respondent shall reply in writing to the charges. The respondent may furnish affidavits and any other documentary evidence in support of the reply. Further, the respondent may elect to—
1. (1) Stipulate to the charges and consent to the imposition of the disqualification order under the conditions set forth in the notice;
2. (2) Make an informal response as provided in § 209.309; or
3. (3) Request a hearing as provided in § 209.311.
(b) The Chief Counsel may extend the reply period for good cause shown, provided the request for extension is served before the expiration of the period provided in paragraph (a) of this section.
(c) Failure of the respondent to reply to the notice of proposed disqualification within the period provided in paragraph (a) of this section or an extension thereto provided under paragraph (b) of this section constitutes a waiver of the respondent's right to appear and contest the charges or the proposed disqualification. Respondent's failure to reply authorizes the Chief Counsel, without further notice to the respondent, to find the respondent unfit for the performance of the safety-sensitive functions described in § 209.303 and to order the respondent disqualified from performing them for the period and under the other conditions described in the notice of proposed disqualification. The Chief Counsel shall serve respondent with the disqualification order and provide a copy of the order to the railroad by which the respondent is employed.