E-book orphaned from paperback?

[Hopscotch]

Would appreciate some advice before I screw up my KDP:  I've a book whose e- and ppbk vers have become disconnected.  The book is there on the Zon for sale in the two formats.  But the separate sale pages don't display "other formats."  What button do a I push to reconnect them?  Or what breed of goat do I sacrifice this time?

[Bill Hiatt]

There should be a "link existing button" on the bookshelf entry for that title. For books where I have both ebook and paperback, I get a "link existing hardcover" option. For books that are only ebooks, I get the hardcover option and a "link existing paperback."

Using the button should be safe as far as I know. It should also be the fastest approach.