Thanks Kevin. Yes, there are various ways of reusing the "final" PDF of a Lulu cover, e.g. by converting it to a JPG and then inserting it into a new cover design, and then repositioning etc. But its CONTENT cannot be changed, of course. I was hoping for something a little more useful, e.g.
I only ever use jpgs. Although at times I Save As a PDF. But if it's the same book, but in hardback, why do you need to change what is on the cover? That's what I assume you mean by content.1. Start a new (hardcover A4) project.
You will need to start a new Project anyway, because it's a hardback, and often will also need a new ISBN if you want Global Dist. Which also needs to go on the Copyright page.2. Upload the proven A4 interior PDF used for the paperback version.
Indeed, because it's not the same Project. But I would suggest Saving the interior PDF under another file name before you upload it. I would expect you will need to add blank pages to the front and back to allow for the different type of binding. Four per end.3. Open the New Lulu Cover Design Tool (as before).
You are going through a Project Wizard are you not? so that is part of the process.4. Choose the blank template, and then the same background colour as before.
4. AND THEN ... ideally select a function to "Insert the cover of an existing Lulu A4 paperback project".
Just upload the paperback's PDF, see what happens.5. The tool would then place all the SOURCE elements of that previous cover in exactly the right places for this identical A4 size book (front, spine and back), i.e. simply leaving the larger hardcover fold/trim areas around the outside of the A4 space.
An A4 hardback is not exactly the same as an A4 paperback.The two key points here, of course, are that:
1. The new cover would still be fully modifiable (background, font sizes and colours, positioning etc ) if that were required (esp. for a slightly different cover text, or a later Volume 2, etc).
2. There would have been no need to start from scratch and replicate the details of each cover element, esp. their fine positioning, to make it look exactly like the earlier paperback version.
When I design a cover I keep all the elements separately, that way they can be pasted differently if need be for another cover.But it looks as though I'll be following the latter, tedious path. It's disappointing that such a simple and common requirement ("Make a Hardcover version of an existing Paperback") is apparently not met by the book and cover design tools.
Welcome to total DIY Self-publishing 
But I do believe that KPD have a one click option that configures different types, but I am not sure how that works with ISBNs. By default Amazon/KDP do not use them.
