Can trustees alter trust document in regard to selecting and removing trustees?
The trust document will have a provision in it as to how it is amended. Sometimes the trustees are able to amend the trust agreement and sometimes that authority is left to the settlors. You need to look at the trust document. The trust agreement, however, has to have a provision for the appointment and removal of trustees (See ERISA section 403). Generally the employer(s) (or association) that is one of the sponsors will appoint the management trustees and the union (the other sponsor) will appoint the union trustees. There can be restrictions put into the agreement as to qualifications to be a trustee. For example some trust agreements require that a managment trustee has to be an employee or principal of a contributing employer. Trustees cannot be appointed for life and ERISA section 411 provides other restrictions.
