Assign manager when manager hire date is later than the employee

Summary

Can't update manager for employee via spreadsheet loader

Content

Hi,

I'm trying to assign managers to employees via the spreadsheet loader. Those employees have currently no manager.

The problem is when the hire date of the manager is later than the employee the update is failed. All I want is to create new update in the employee's assignment record for a new manager, I could not understand why it doesn't work? Why the effective date has to be equal to the hire date of the employee?! It doesn't make any sense.

I was trying the solutions which provided in the following posts but it didn't work for me - 1.