Need to cancel schedules that are currently executing
Go to Reports and locate the report on the list. Highlight and click on Edit Schedule. In the Schedule box, change the 'Ending on' option to Number of Occurrences. Set it to 'End After' 1 Occurences and set the 'Recurrence' to None. Change the 'Start Date' to a date in the past.
If the memorized report is no longer required, delete the report and the schedule.