The correct way to make someone a leaver is to process what is owed to them by organising their final pay first and then add a leave date in the ‘left’ box under the employee. You can then move forward into the next period which will cease any further payments and allow you to file the FPS which notifies the HMRC of the PAYE information as well as the leaving information.
One common issue is that final payment has been processed and the leaving date has been entered after moving forward to the next period, as you have moved forward 12Pay will assume that this employee is still due to be paid.
The best way around this is to complete a rewind to redo (KB10001) to the same month that you are processing now which will let you amend their wage, you can then update the employee as ‘dormant’, you can do this by selecting the ‘Personal’ tab and putting a tick in the ‘dormant’ tick box in the centre.
This will remove any PAYE information from the employee for that period and therefore the employee will not be paid incorrectly after they have left.