Private contracts among interested persons.

Subject to the rights of creditors and taxing authorities, interested persons may agree among themselves to alter the interests, shares, or amounts to which they are entitled in a written contract executed by them. The personal representative shall abide by the terms of the contract, subject to the personal representative’s obligation to administer the estate for the benefit of interested persons who are not parties to the contract, and to pay costs of administration. Trustees of a testamentary trust are interested persons for the purposes of this section. Nothing in this section relieves trustees of any duties owed to beneficiaries of trusts.