Not able to update bpm:assignee property of task using Java API

[java]

Hello, i am new to Alfresco. I am creating and managing workflow using REST API(front end is PHP). When i am trying to update a  task assignee, value doesn't change. 

props.put(WorkflowModel.ASSOC_ASSIGNEE, assignee);

serviceRegistry.getWorkflowService().updateTask(taskId, props, null, null);
serviceRegistry.getWorkflowService().endTask("", "");

Any suggestion??

Thanks in Advance.

[ryandawson]

Presumably you're using the ECM/content repository? If so it would be best to post the question under the ECM forum. But there is a post on that forum already which might answer your question - reassign one user task to other user through java