20 C.F.R. § 404.977 : Employees' Benefits — SOCIAL SECURITY ADMINISTRATION — FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) — DETERMINATIONS, ADMINISTRATIVE REVIEW PROCESS, AND REOPENING OF DETERMINATIONS AND DECISIONS —APPEALS COUNCIL REVIEW — Case remanded by Appeals Council

(a) When the Appeals Council may remand a case. The Appeals Council may remand a case to an administrative law judge so that he or she may hold a hearing and issue a decision or a recommended decision. The Appeals Council may also remand a case in which additional evidence is needed or additional action by the administrative law judge is required.
(b) Action by administrative law judge on remand. The administrative law judge shall take any action that is ordered by the Appeals Council and may take any additional action that is not inconsistent with the Appeals Council's remand order.
(c) Notice when case is returned with a recommended decision. When the administrative law judge sends a case to the Appeals Council with a recommended decision, a notice is mailed to the parties at their last known address. The notice tells them that the case has been sent to the Appeals Council, explains the rules for filing briefs or other written statements with the Appeals Council, and includes a copy of the recommended decision.
(d) Filing briefs with and obtaining evidence from the Appeals Council.
(1) You may file briefs or other written statements about the facts and law relevant to your case with the Appeals Council within 20 days of the date that the recommended decision is mailed to you. Any party may ask the Appeals Council for additional time to file briefs or statements. The Appeals Council will extend this period, as appropriate, if you show that you had good cause for missing the deadline.
(2) All other rules for filing briefs with and obtaining evidence from the Appeals Council follow the procedures explained in this subpart.
(e) Procedures before the Appeals Council.
(1) The Appeals Council, after receiving a recommended decision, will conduct its proceedings and issue its decision according to the procedures explain in this subpart.
(2) If the Appeals Council believes that more evidence is required, it may again remand the case to an administrative law judge for further inquiry into the issues, rehearing, receipt of evidence, and another decision or recommended decision. However, if the Appeals Council decides that it can get the additional evidence more quickly, it will take appropriate action.

20 C.F.R. §404.977