34 CFR § 690.75 - Determination of eligibility for payment.
(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) Qualifies as an eligible student under 34 CFR Part 668, Subpart C;
(2) Is enrolled in an eligible program as an undergraduate student; and
(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.
(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.
(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.