how to change pay rate and effective date for retro pay%0D%0A

I can help you with that, KA311.

You can open the employee's profile to update their pay rate. Take note that there are different ways to issue a retroactive payment to your employee in QuickBooks. 

The first option is to create a lump sum payment on a separate check. Alternatively, you can include the retro pay in the employee’s next paycheck and label the amount as RETRO. The last one is adding the pay to their regular paycheck without labeling. 

When you're ready, follow these steps to change the rate of your employee and the effective date:

1. Go to the Payroll menu.
2. Select the Employees tab.
3. Click the name of the employee.
4. Head to the Pay types section, then select Edit.
5. Enter the new rate and make the other necessary changes.
6. Click Save.

If you have further questions about payroll, don't hesitate to post them below. I'm always here to assist.