National Medical Support Orders and Retiree Coverage

Multi-employer, government-sponsored (technically non-EIRSA) cafeteria plan that provides pre-Medicare retiree coverage.  Question concerning a recent pre-65 retiree who has a NMSO in effect for dependent coverage.  Retiree wants to drop coverage in favor of HRA-only waiver because other coverage is available through spouse.

I believe we are still considered an "employer" for purposes of the NMSO and cannot allow the retiree to drop coverage without an amendment to the NMSO, but have been unable to find guidance on this question anywhere.  Anybody else dealt with such a situation?