Exporting a Report Template
To export a report template from PowerSchool you first go to that report:
Start Page > Reports > Report Setup > Object Reports  and select the report you want to export.
At the bottom of that report, there is an "Export this report as a template" right click on it and "Save Link As" and it will give you the option to save the report.
To import the report back in, follow these instructions:
Importing Report Templates Into PowerSchool