It took me a while to figure out that paragraph data in Magnolia is always associated with the paragraph template that it was originally created with. So, if your content authors use a sampleTextImage paragraph style to add content to a page while you are developing custom templates for the site, you wont be able to change the paragraph Template that the content is associated with.

The two solutions I have found are:

1. Export the site tree to XML and do a find and do a find and replace in a text editor to change <sv:value>samples to the name of your custom paragraph template. This is NOT a very good solution. If you are dealing with any heavy binary in your site tree (i.e. PDFs, movies, hi-res graphics) a find and replace can take a long time, or even crash your editor.

2. Welcome to a much more elegant solution #2. Create a custom page template with code that searches out all the required paragraphs and changes them. By template here, I mean page template, not paragraph template. Just set the page to use this new utility template and load it in your browser once, the code executes changing the paragraph template associations, then re-apply the original page template. Your paragraphs should now be using your new custom paragraph templates.

I love to see more utility templates =). This one is great. See attachment!