How to make massive changes to my book?

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Making massive changes

The short answer is: "Don't. Ask first!" The reason is simple: there is often an easier way to achieve your purpose. Also, massive changes to any content may have unintended consequences.

Changing the outline

If you want to change the outline of your Personal Book, moving one page from one place to another, do not attempt to delete the page to recreate it in the new place. It won't work. Check the following page, and ask for help:
http://en.minguo.info/wiki/how_to_organize_a_book_structure_outline
There is a very easy method to move a page.

Repurposing a page

Do not "repurpose" a page, by completely rewriting its content, changing the title, the body of the article, etc. The unintended result might be that links previously established might no longer link to the intended content. You'd be misleading the potential readers of your articles. Ask first about what might be the best way to accomplish what you are after.