(a) While a trust is revocable and the grantor has capacity to revoke the trust, rights of the beneficiaries are subject to the control of, and the duties of the trustee are owed exclusively to, the grantor.
(b) During the period the power may be exercised, the holder of a power of withdrawal has the rights of a grantor of a revocable trust under this section to the extent of the property subject to the power.
(c) When a trust is revocable, the trustee may follow a direction of the grantor that is contrary to the terms of the trust instrument.