Apple ID linked to wrong @icloud.com account.....

Somehow my Mom's apple id has my @icloud.com account in the alternate emails for contact and when I tried to delete it, there was no option only a question mark saying that it's a primary alias. How do I remove and replace it? Idk how it happened as nowadays when you make an apple id it also makes an iCloud account but maybe it happened before this was a thing nevertheless what to do now??