This isn't something you can do within Pay & Bill from an application side.
The FPS (Full Payment Submission) is generated with the Period dates and these are what are sent to HMRC for payments.
This would need to either be done via the HMRC PAYE Online Tools, which can be downloaded from the HMRC website, to manually send these adjustments over to your account or this would need to go through the Professional Services chargeable route, as these FPS files would need to be manually built in the database pulling all the required data from the necessary tables.
If you would like to follow the latter, please speak to your Customer Success Manager or Account Manager to discuss this.