Increase part time to full time

I forgot to change the normal working hours from part time to full time for one employee.  What is the best way to correct this?

Do I need to re-enter in 15 payslips to correct the annual leave and holiday pay entitlements or is there another way around this that may be easier.  I just don't want to re-enter in all the payslips for the other ones that are correct.  Lesson definitely learned!

Start date 03/05/2021.  Casual part time.  Full time hours started on 01/04/2022.

Any help would be appreciated.

Many thanks