Vt. Stat. Ann. tit. 18, § 1608

Any party state may withdraw from this compact by enacting a statute repealing the same, but no such withdrawal shall take effect until one year after the governor of the withdrawing state has given notice in writing of the withdrawal to the governors of all other party states. No withdrawal shall affect any liability already incurred by or chargeable to a party state prior to the time of such withdrawal.