How to re-apply a report template to an existing report
From your root control panel, navigate to the "Reports" section.
Tick the box(es) next to the report(s) where you'd like to reapply a template. Then, click "Apply Template" at the top of the column.
Choose the template to apply, then click "Apply Template"
The template will then overwrite the existing contents of the report.
Note: Please use caution. Once overwritten, the previous contents of a report cannot be recovered.