Beneficiary Designation Right. Except as provided in Section XXX and to the
extent the form of benefit so provides, each Participant, and if applicable Beneficiary, shall have the right to designate one or more primary and one or more secondary Beneficiaries to receive any benefit becoming payable upon such individual's death to the extent provided in the Adoption Agreement. All Beneficiary designations shall be in writing in a form satisfactory to the Plan
Administrator and shall only be effective when filed with the Plan Administrator during the Participant's lifetime (or if the Participant has died, during the lifetime of the Beneficiary of such Participant who desires to designate a further Beneficiary). Except as provided in Section XXX, each Participant (or Beneficiary) shall be entitled to change his Beneficiaries at any time and from time to time by filing written notice of such change with the Plan Administrator. In the event that the Participant fails to designate a Beneficiary, or in the event that the Participant is predeceased by all designated primary and secondary Beneficiaries, the death benefit shall be payable to the Participant's spouse if then surviving, and if not, to the Participant's children in equal shares and if none, to the executor or administrator of the Participant's estate.
Check to see if you have this clause in your Plan documents. Your participant should be able to change his beneficiary at any time, as long as it's in writing to the PA.