There is no way to restore a cancelled work order, but it is possible to duplicate the cancelled work order. Below are the steps:
1. You can copy work order by right-clicking on the cancelled work order:
2. Mark the "Data from the original work order" check-box, and click "Save":
3. A new work order will be generated with the data from the original work order as recommended.
NOTE: The data from the cancelled work order is not calculated in the reports.