CFR › Title 20 › Part 366Part 366 — Collection of Debts by Federal Tax Refund Offset§ 366.1— Notification to Internal Revenue Service.§ 366.2— Past-due legally enforceable debt.§ 366.3— Reasonable attempt to notify.§ 366.4— Notification to debtor.§ 366.5— Consideration of evidence.§ 366.6— Change in notification to Internal Revenue Service.