39 C.F.R. § 3006.203
(b) Requirements for making an appeal. A requester may appeal an adverse decision on their FOIA request rendered by the Commission by submitting a hard copy to the Commission's office (901 New York Avenue NW, Suite 200, Washington, DC 20268-0001) or by emailing FOIA@prc.gov. The requester must make the appeal in writing and to be considered timely it must be postmarked, or in the case of electronic submissions, transmitted, within 90 calendar days after the date of the Commission's response. To facilitate handling, the requester must mark both the appeal letter and envelope or the subject line of the electronic transmission “Freedom of Information Act Appeal.” The appeal must include, as applicable:
(c) Adjudication of appeals.