Thank for your reply Pete. I tried nested conversation without success. The problem is that you get the same persistence context even if you use two components. I didn't find a solution with JTA as well : - Start a transaction with entity manager 1 - Persist the parent - Start a transaction with entity manager 2 - merge the parent in the new persistence context - create a child - add it to the parent - persist the child - commit the transaction - close entity manager 2 - rollback transaction (EM 1) => parent is rolled back but the child is in the database because of the commit in the nested transaction. Do you mean something different by "roll back changes on cancel" ? How can you use detached entities to solve this problem ? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4052819#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...