Well, editors do have the potential to change things in novels. They might do it to make the story more coherent, appealing to a wider audience, or to meet certain publishing standards. But not all edits are major; some could be minor tweaks.
Sometimes they do. It depends on various factors like the quality of the initial draft and the editor's vision for the book.
Editors can make changes, but it varies. They might correct grammar, tweak the plot for better flow, or enhance character development. However, the extent of changes can differ from one novel to another.