About the permission right of deleting customer attributes

Hi team, 

My client is asking how to delete the non-used customer attributes from people core services UI. They can saw the deleted function on UI (as the "2" on screenshot, sorry for mandarin UI), but the notification would be popped to show lack of permissions (as the "3" on screenshot). They would like to know what kind of permissions needed to grant for Customer Attributes deleting.

Regards