A defendant cannot directly petition a court for compassionate release based on substantial assistance to bypass Rule 35(b)’s requirement that the government file a motion for sentence reduction exclusively on this ground

18 U.S.C. § 3582(c) provides various routes for a District Court to reduce a defendant’s sentence after sentencing. Subsection (c)(1)(A) permits courts, as modified by the First Step Act, to directly receive a defendant’s motion for compassionate release 30 days after he has requested such relief from his warden. This subsection requires consideration of the 3553(a) factors and a finding that “extraordinary and compelling reasons warrant such a reduction.”

Subsection (c)(1)(B) permits a sentence modification if “expressly permitted by statute or by Rule 35 of the Federal Rules of Criminal Procedure.” Rule 35(b) only permits sentence reduction one year after sentencing based on a defendant’s substantial assistance upon the government's motion. 

In United States v. Claude, https://www2.ca3.uscourts.gov/opinarch/203563p.pdf, the Third Circuit held that a defendant may not use the compassionate release process to bypass Rule 35(b)’s requirement that the government bring a motion for sentence reduction based on a defendant’s post-sentencing substantial assistance in investigating or prosecuting another person. While a defendant cannot satisfy the “extraordinary and compelling reasons” standard for compassionate release based on his unilateral evaluation of his assistance, a District Court may consider such assistance in its compassionate release analysis. It can be “a relevant factor” just not serve as the only basis to establish extraordinary and compelling reasons.