The Supreme Court has defined remands under section 405(g).
Under sentence four, a district court may remand in conjunction with a judgment affirming, modifying, or reversing the [Commissioner's] decision. Under sentence six, the district court may remand in light of additional evidence without making any substantive ruling as to the correctness of the [Commissioner's] decision, but only if the claimant shows good cause for failing to present the evidence earlier.
Melkonyan v. Sullivan, 111 S. Ct. 2157, 2164 (1991). In Shalala v. Schaefer, [cite] (1993), the Supreme Court instructed that sentence four and sentence six remands are the exclusive methods for courts to remand Social Security cases to the Agency, noting that "[s]entence six remands may be ordered in only two situations: where the Commissioner requests a remand before answering the complaint, or where new, material evidence is adduced that was for good cause not presented before the agency." Id. at, n.2. Attorneys should routinely object to retention of jurisdiction by a district court after a sentence four remand.
[cited in JM 4-6.397]