If you have already registered a Product Announcement, navigate to Product Announcements in you [ List of Works ] ,and go through the retail registration via the "Final Registration" button.
After completing registration via the "Final Registration" button, when the product goes on sale, the Product Announcement page will redirect to the URL of the product page. As such, there is no need to delete the Product Announcement page.
If you use [ New Product Registration ] instead, the two registrations will be treated as separate products, and users who have added the announced product to their Favorites will not be notified when it goes on sale.