Settlor's powers; powers of withdrawal\n(a) While a trust is revocable and the settlor has capacity to revoke the trust, rights of the beneficiaries shall be subject to the control of the settlor and the duties of the trustee shall be owed exclusively to the settlor.\n(b) During the period the power may be exercised, the holder of a non-lapsing power of withdrawal shall be treated, for purposes of this section, as if the holder of the non-lapsing power of withdrawal were the settlor of a revocable trust to the extent of the property subject to the power.
Massachusetts Legal Code