How to unclaim a task

Hi there,
I want to unclaim the task after it is claimed and worked.So the remaining part of the work should be done by someone else…

I have used…
task=taskService.createTaskQuery().taskCandidateGroup(“Employees”).singleResult();
taskService.claim(task.getId(),“vamsi”)

Now i want to unclaim the user vamsi and should be again claimed by some one else

Passing null value to the userid will unclaim the task.

taskService.claim(task.getId(), null);

Thank you…