I found how to do it.
Thanks everyone.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
if ( newState!=null ) {

IProcessArea processArea = getProcessServerService().findProcessArea("Garbage", null);


IWorkItem workingCopy = (IWorkItem)newState.getWorkingCopy();
IWorkItemReferences workItemReferences = getWorkItemService().resolveWorkItemReferences(workingCopy, null);

WorkItemWrapper wiWrapper = new WorkItemWrapper(workingCopy, workItemReferences, "");
ServerCopyToProjectOperation op = new ServerCopyToProjectOperation(processArea.getProjectArea(), true);
op.run(wiWrapper, getWorkItemService());

done=true;
getWorkItemService().saveWorkItem2(workingCopy, null, null);

}

Dear

I'm developing a server plug-in that moves workitem from a project area to another.

When status of workitem is in invalidated, it should be moved to another project area. So I'm developing a server plug-in for this.

I'm looking for APIs for that, but I can't find it.

Can anybody provide a pesudo-code for this purpose?

Any help will be appreciated.