How to cancel work relationship via HDL if there are direct reports on previous assignment records

Summary:

How can we cancel work relationships via HDL when there are direct reports on previous assignment records - manual intervention is not possible for potentially thousands of impacted records.

Content (required):

We have a requirement to cancel the work relationships of around 1500-2000 employees, however we receive an error message when trying to do so via HDL:

"You cannot cancel this working relationship because the person has direct reports in at least one assignment"

We have removed the direct report(s) from the current assignment record but there are direct reports on prior assignment records. We cannot check every employee to reassign every historical direct report manually, this would equate to thousands and thousands of records. Does anyone have a suggestion as to how we can achieve this via HDL? Or is there a way to reassign all historical records to one current employee so that we can then cancel the work relationships? Any guidance would be appreciated. Thanks.