Rule 35(a)'s clear-error authority and 14-day period measured from oral sentencing.
Rule 35(b)'s government-motion, timing, substantial-assistance, and statutory-minimum rules.
Rule 36's at-any-time clerical-error authority, distinct from substantive modification.
Material limitations
The rules do not resolve whether a particular error is clerical or clear, whether substantial assistance occurred, or the limits on reviewing a government decision not to move.