Navigate to the report whose properties you wish to edit, and hover over the "Report Sources" to find the report segments (data sources) chosen. Click on it to open the report settings.
In the popup that appears, you can change the name and report segments of the report. You can also choose a limited set of metrics and dimensions to be shown on the report. Report segments can be native segments or custom segments. Native segments here are the advertising channels, the analytics sources linked to these advertising channels get included automatically.
Learn more about the report segments.
Learn more about choosing metrics and dimensions.
Click "Update Report" once you're done with the changes. On saving the changes, you will receive a "Report updated successfully" alert.
Learn more about the overall structure of a report.