If a scheduled report is no longer needed prior to the scheduled "end date", you can stop the scheduled report so the recipient(s) will no longer receive it.
Stop a scheduled report
Go to Reports > Reports
Click the "Edit" icon next to the scheduled report. This will take you to the last page of the report builder
De-select the "Schedule the Report" checkbox. This will deactivate the scheduling of the report
Make sure there is a check icon under the "Scheduled" column as this is an indicator that the report is scheduled
You can remove the scheduling without removing the report itself