Cancel an existing workflow when it is no longer
  required. This deletes all tasks related to the
  workflow.
    This task assumes you are on the Workflows I've Started
    page.
    - In the workflow list locate the workflow you want to cancel and position your cursor over it to reveal the available actions.
 - 
        Click Cancel Workflow.
        
A message prompts you to confirm the action.
 - 
        Click Yes.
        
The selected workflow is cancelled and removed from the workflow list. All tasks related to the workflow are deleted, which removes them from the assignees’ task lists.