How can I edit the worker category in workplace pensions of a new employee at the end of 3 months of postponement from elibible to entitled?

Hi there, nick. I can share details about enrolling an employee for workplace pension in QuickBooks Online (QBO).

Since you mentioned rerunning payroll transactions, we can no longer change a pension category for employees who have been ran a payroll. Moreover, we can consider the following suggestions if you prefer to change the employee's pension category.

First, we can roll back to the employee's start date to change the pension worker category in QuickBooks Standard Payroll. I'll show you how:

1. Go to the Payroll menu and click on the Pay History.
2. From there, tap on the Pay period.
3. Drill down the Actions and select Delete Payroll.

Other than that, we can opt to migrate to the Advanced payroll in the new tax year to change and enroll the employee in the pension. 

Furthermore, you can visit these resources in managing your employees and following the guidelines for setting up workplace pensions:

• Edit employees in QuickBooks Online Standard Payroll
• Set up workplace pensions in QuickBooks Online Standard Payroll 

I'll keep this thread open if you have additional questions about payroll. The Community always has your back. Stay safe!