Employee wise Revision:
Go to Employees >> Click More >> Under Salary Revision Management >> Click Employee Wise Revision >> Select the month and Employee Code and click on Delete
Bulk Revision
In the same path, select Bulk Revision >> Click List >> Month >> Code and Name >> click Search >> Check/Tick on Particular employees and click on Flush
Note: If an increment is being processed and payroll month is locked (example: July) later that specific month’s increment data cannot be deleted/modified.
So, before any modification do unlock the payroll of that month and delete.
http://support.paybooks.in/support/solutions/articles/4000093080-why-when-and-how-to-unlock-payroll-