HMRC allow you to file the last period submitted as many times as you want to make corrections. However once you move onto the next period, any corrections would need to be done at the year end by way of an EYU - Earlier Year Update. For example if you have filed month 2 you can resubmit month 2 to make any corrections. Once month 3 has been submitted you cannot refile anything earlier. To file the FPS you would make the necessary changes to the pay period for the affected employee(s) and then run the FPS report. When you click to submit, if it is now past the payment date, it will ask you to select a reason for the late submission. You can select the option "correction to an earlier submission".