You can only edit report templates belonging to you or the organisation to which you belong (assuming you have the necessary admin privileges).

To edit a report template go to your Report Template Library from the dashboard. The name of the report templates that you can edit show as a hyperlink, the name of the report templates that you can’t edit don’t.

To edit the name and tags of a template click on the corresponding edit icon. 

To edit the content of a report template, click on the name and you will be directed to the Report Template Builder for that template. You can then add / remove sections, and add / edit content within a particular section in the usual way just as you would if you were editing a report within the Report Builder.