3820850 - How can I remove and add all list items in bulk via imports?

I have troubles with our company hierarchy, as some of the items are not there, therefore I cannot assign the authorized approvers for the cost objects if they don't exist in the hierarchy (list). How can I delete complete list and add a new list.
- OR -
I need to remove all list items and then create a new list.

I would need to add or delete list items through imports, is there a way to do it. , KBA , CON-CA-TLS-IEM-JOB , Scheduled Jobs , Problem