Sometimes within NaturalHR a workflow step might be stuck as incomplete, for example if the workflow step assignee is out of work and therefore cannot access the step in order to complete it. Fortunately HR and admin level users are able to manually complete workflow steps in order to progress workflows so they can be 100% complete.
In order to enable this option navigate into Administration -> Company -> Settings -> Company Settings.
Once on this page scroll down to the Workflow Settings section and change the 'Allow triggered workflows to be updated' field to Yes:
This will then allow your HR and admin users to mark the steps as complete. Additionally if they click the pencil icons on a workflow step they can adjust the assignee to a different employee and change the Due Date to a different date too.