Trust Funds

If the beneficiary of an irrevocable trust feels that the trustees are mismanaging her trust fund (not as a criminal matter, but making investment mistakes that are seriously weakening the trust), what can she do about it? Is there a governing authority to whom she can appeal? Does she have to sue? Thanks for the help.

What state law is the trust governed by? Generally, a trustee is subject to the "prudent investor rule," which is relatively vague, but is generally the starting point.