20 Pa.C.S. § 7780.1: Enforcement and defense of claims - UTC 811.

Except as provided in section 7770 (relating to liability of successor trustee), a trustee shall take reasonable steps to enforce claims of the trust and to defend claims against the trust. When one of several trustees is individually liable to the trust, the other trustee or trustees shall take any legal action against that trustee necessary to protect the trust.