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.