To convert a fanfic to an original will be time-consuming and a lot of work, but it can truly pay off in the end if done properly. First, start off by making sure to copy your original doc/folder just in case you decide this isn't what you want to do. Work in the "copy" to preserve your original doc. Then, create names for your characters, and make sure each time they are mentioned, the names are changed. Then remove any signs of whatever your fanfic is about. This is where adding and rewriting some things will be required. Like I said, it is a lot of work, but it can be quite satisfying if done correctly.
