I am trying to change a judgement into a garnishment for spousal support social security has already determined I am entitled to up to 80% of his s.s.

Rather than a garnishment, I believe you are talking about an income assignment or marital income disbursement order. Child support orders and spousal support orders from a divorce or separation can be enforced by way of a wage assignment. You should be able to contact the family court division-clerk of courts in the county where your case is, and they will send you the form to complete.