Want to insert a termination and rehire record restrospectively for an employee

We have an employee who should have been terminated in 2018 and rehired again in 2019, however unfortunately this was not done and so they now have only one period of service when they should have been rehired and have second period of service.

This employee as you can imagine has a number of assignment changes since 2018 e.g. salary increases along with a number of element entries, absence records, performance records etc.

I know I can delete the assignment changes back to 2018 and then enter the termination and rehire them but all that associated data since 2018 will be lost and was wondering if anyone has faced a similar situation and know a clever way to enter/insert the termination and rehire into their assignment changes so the associated data will not be lost?