Removal of divoriced spouse as beneficiary on retirement pla

I am trying to remove my divorced spouse as beneficiary from my retirement plan at my work. It appears that I can not remove him without an equitable distribution order. I don’t have one because we decided among ourself how property was distributed. We separated in January of 2001 and divorced in March of 2003. What documentation do I need to remove him and be able to draw a sum from my account?

The divorce decree should suffice.