14 CFR § 13.47 - Withdrawal or amendment of the complaint, answer, or other filings.

(a) Withdrawal. At any time before the hearing, the complainant may withdraw the complaint, and the respondent may withdraw the request for hearing.

(b) Amendments. At any time more than 10 days before the date of hearing, any party may amend its complaint, answer, or other pleading, by filing the amendment with the FAA Hearing Docket and serving a copy of it on every other party. After that time, amendment requires approval of the hearing officer. If an initial pleading is amended, the hearing officer must allow the other parties a reasonable opportunity to respond.