Approved PRD Modify Action of RIF PRD Demonstrates the modify action in RIF PRD. The rule modifies the customer frame object with a discount value of "0". Note, the modify action is like an atomic retract+assert action. Modify-premise.rif http://www.w3.org/2005/rules/test/repository/tc/Modify/Modify-premise.rif ) Prefix(xs ) Group ( Forall ?X ( If ?X[ex:status -> "normal"] Then Do ( Modify (?X[ex:discount -> "0"]) ) ) ex:john[ex:status -> "normal" ex:discount -> "10"] ) ) ]]> Modify-conclusion.rif http://www.w3.org/2005/rules/test/repository/tc/Modify/Modify-conclusion.rif "normal" ex:discount -> "0"] ]]>