5 C.F.R. § 2634.409
An interested party may place a pre-existing irrevocable trust into a qualified trust, which may then be certified by the Office of Government Ethics. This arrangement should be considered in the case of a pre-existing trust whose terms do not permit amendments that are necessary to satisfy the rules of this subpart. All of the relevant parties (including the employee, any other interested parties, the trustee of the pre-existing trust, and all of the other parties and beneficiaries of the pre-existing trust) will be required pursuant to section 102(f)(7) of the Act to enter into an umbrella trust agreement. The umbrella trust agreement will specify that the pre-existing trust will be administered in accordance with the provisions of this subpart. A parent or guardian may execute the umbrella trust agreement on behalf of a required participant who is a minor child. The Office of Government Ethics has prepared model umbrella trust agreements that the interested party can use in this circumstance. The umbrella trust agreement will be certified as a qualified trust if all of the requirements of this subpart are fulfilled under conditions where required confidentiality with respect to the trust can be assured.
5 C.F.R. §2634.409