>i want to update the user who acted on first task but the data should be in content table so that i cna use it for display purposes.
Is this like accessing data from a content table (e.g, say you application database table) and updating user?
You can use a script node (http://community.jboss.org/people/bpmn2user/blog/2011/03/30/jbpm5-example--human-task-forms-with-variables--workitems) that can access your content table.