Reports that create a contact code, eg. Service Reminders, Booking Reminders etc need the batch reset before they can be re-run for the same date range.
To identify the batch that needs to be reset,
CRM > Reports & enquiries > Report generator > Run report generator > K04
Enter the Contact Code, which will be same as the report code you are trying to re-run in most cases.
Note down the Contact Date and Batch No from the result displayed:
Then run K99 from same place.
CRM > Reports & enquiries > Report generator > Run report generator > K99
If you get a warning as below, please click OK
Enter Batch No and Date and Click OK as shown below:
This would reset the previous batch allowing you to re-run your report as per normal.