46 CFR 541.8: Requests for fee mitigation, refund, or waiver.

(a) The billing party must allow the billed party at least thirty (30) calendar days from the invoice issuance date to request mitigation, refund, or waiver of fees from the billing party.

(b) If a billing party receives a fee mitigation, refund, or waiver request from a billed party, the billing party must attempt to resolve the request within thirty (30) calendar days of receiving such a request or at a later date as agreed upon by both parties.