No provisions of this Act shall relieve, impair, or affect any right, duty, liability, or obligation arising out of any contract, concession, lease, or franchise now in existence, including all contracts entered into by Bristol Virginia Utilities except to the extent that such contract, concession, lease, or franchise may permit. Notwithstanding the foregoing provisions of this section, the Authority may renegotiate, renew, extend the term of, or otherwise modify at any time any contract, concession, lease, or franchise now in existence in such manner and on such terms and conditions as it may deem appropriate, provided that the operator of or under any said contract, concession, lease, or franchise consents to such renegotiation, renewal, extension, or modification. The Authority shall be obligated for the performance of any contract of Bristol Virginia Utilities now in existence in accordance with its terms, and such contracts shall remain in full force and effect.