How to Update Accrual Plan Enrollments as of last assignment change date instead of effective date

Summary:

How can we run the Update Accrual Plan Enrollments process and have the enrollment start date match the date of the assignment change, rather than the process effective date?

Content (please ensure you mask any confidential information):

We discovered that Update Accrual Plan Enrollments has never been scheduled to run, and our employees who have assignment changes which alter their eligibility for absence plans have not been having their plan enrollments updated automatically.

We have three years of absence plan updates to make. What is the best way to run the process to 'catch up' before we schedule it, and ensure the enrollment start dates of the plans is set to the date of the assignment change?