Workflow task set to completed by mistake

Question

I would like to learn if it is possible to set back the state of a workflow created task from Completed back to Not Started state.

Answer 1

If it's completed you can just start a new instance of the workflow on the item. It's not possible to rewind an existing instance.

Use the context menu on the list item, click on Workflows and under Start a New Workflow pick the appropriate workflow.

http://msdn.microsoft.com/en-us/library/cc748597.aspx

See steps 11-13.