The way the marketer can satisfy the request to permanently delete a prospect from Marketing Cloud Account Engagement is by archiving the prospect and then selecting "Permanently Delete" from the recycle bin. Archiving a prospect removes them from the active prospect database and places them in the recycle bin, where they can be restored or permanently deleted. Permanently deleting a prospect removes them from Marketing Cloud Account Engagement and Salesforce completely and cannot be undone. The marketer cannot archive the prospect without permanently deleting their data, as the archived prospects still count towards the database limit and can be restored. The marketer cannot delete the prospect in Salesforce, as this will only archive the prospect in Marketing Cloud Account Engagement, not permanently delete them. The marketer cannot go to the prospect record and choose the "Permanently Delete" menu option, as this option is not available on the prospect record, only on the recycle bin. Reference Deleting Prospects