I don't want to delete the secondary iCloud account? How do I change the primary account without deleting the old primary account!?

We want to change the Primary iCloud account on one of the businesses computers and all it tells us is to delete it. We don't want to because we're afraid this will also delete all the meetings and other things saved on this account. Can anyone tell us how to simply change and not delete. Or can you let us know if you do lose anything if you delete an iCloud account??

Thanks