Times change, people change; do trusts change? With an aging population and one of the largest anticipated wealth transfers in recent history, families and advisers should review existing trusts to determine their utility and alignment with current client goals and tax laws. This review may lead some to question how "irrevocable" is an irrevocable trust, as well as when or how these trusts may be modified or terminated. This article describes how to modify or terminate these trusts, analyzes some key issues and potential pitfalls, and highlights some best practices.