34 CFR §690.75

1. (a)For each payment period, an institution may pay a Federal Pell Grant to an eligible student only after it determines that the student—
   1. (1)Qualifies as an eligible student under 34 CFR part 668, subpart C;
   2. (2)Is enrolled in an eligible program as an undergraduate student; and
   3. (3)If enrolled in a credit hour program without terms or a clock hour program, has completed the payment period as defined in § 668.4 for which he or she has been paid a Federal Pell Grant.
2. (b)If an institution determines at the beginning of a payment period that a student is not maintaining satisfactory progress, but reverses that determination before the end of the payment period, the institution may pay a Federal Pell Grant to the student for the entire payment period.
3. (c)If an institution determines at the beginning of a payment period that a student is not maintaining satisfactory progress, but reverses that determination after the end of the payment period, the institution may neither pay the student a Federal Pell Grant for that payment period nor make adjustments in subsequent Federal Pell Grant payments to compensate for the loss of aid for that period.