How to remove a workflow instance?
In some cases, a workflow needs to be removed from the 'Work Items' list.
Steps:
1.Open "Management Console".
2.Open "Excel Report"
3.Find the report that contains that workflow.
4.Right click the report and choose "Properties".
5.Click "Workflow", and find the instance to be removed, then click "Remove the Workflow".
6.The workflow is removed.