Portrait Auto Flow single pages and page spreads can be deleted from the yearbook. The process is the same as deleting regular pages in the yearbook. This article will show you how:
Note: If you delete a Portrait Auto Flow page you will not be able to retrieve the page with the portraits to add back to the yearbook. You will see the pages in My Pages>Deleted Pages but when they are added back to the yearbook they will not include the portraits.