1. Identify the error
This may seem obvious but it may not be so straight forward. If you find that there is an error, you will need to identify the source of the error so you can correct it. If for example, you added holiday pay and the amount you added to the employee was incorrect, then you may identify the source of the error as human input. You may have added incorrect hours for an employee that is paid hourly. These are relatively simple fixes.
How about if the error is a little more difficult. For example, the car benefit amount was incorrect, or the person accidentally didn't have backpay added or was submitted with his or her pay calculated using the wrong tax code. All of these things do happen once every so often, so going back and fixing these issues is not as rare as you might think.
2. Decide how to correct the error
Once you've established the error, there are two things you can do. You can either reverse the payroll run, and then correct the error, and then resubmit specifying a late reason (typically this would be 'Correction") when the payroll modal asks why the payroll is being run after the payment date.
Can the error be rectified in the next pay run?
An alternative is to correct the error in the next pay run. For example, if you have underpaid an employee, then you can simply add the back pay to the next pay run. This is done by adding the employee to the payroll and then clicking on the edit button next to the employee name. Perhaps the employee cannot wait until the next pay run. Should that be your problem as the employer? Employees often try and pressure others to do things they need done, and vice versa. The way to think about this is how necessary it is.
There are two things you can do in this instance. You can either reverse and re-run the payroll, or you can pay out the correct amount to the employee. And make a note that the employee has been paid the correct amount but the adjustment needs to be made on the next pay run. Clearly if the error is a small one, for example £100, you could do this. However, if the error is £10,000 then it might make sense to re-run the payroll. Alternatively, if the employee must be paid, you can pay the adjusting payment as a loan from the company that is to be cleared by the next pay run.
Obviously these things complicate the initial error so many employers would not bother doing this. It would see smarter to reject the employee's 'need' to be paid immediately and to pay out in the next pay run.
3. What happens if the error was administrative?
Perhaps it isn't the amount on the employee pay that is incorrect but the employee details. Perhaps you got the NI number or tax code incorrect. There's no need to fret. You can simply update the tax code and NI on the pay run. In fact, HMRC may even send you an updated tax code for the employee to use for the next pay run that takes into account that fact that the employee may have over or under paid. Ideally, if you have PAYE messages set up on your account, you will get the message in time. If you don't have it setup on your online account, then it will more likely be mailed to you and may not even arrive before the next pay run!
Summary
There are 2 options when you have an FPS error.
You can reverse the payroll, remove the employee from the pay run to ensure the cached details are deleted and then re-add the employee after you've made the adjustments in the employee profile. Once you re-add the employee, you can edit the profile as normal. Then run the payroll with the correct payment date and choose the late reason, for example, correction.<
You can wait to the next pay run and make the adjustments there. For example, back pay or salary deductions can be made from an employee that is added to the payroll, and this will then bring the correct YTD figures for the employee after you submit.