Identifying the program in use would be valuable. Paint Shop Pro has a native format to maintain previous work. I suspect the editor you are using would support something similar.
If you want to keep the original RAW image, don't overwrite it, regardless of the editor you are using. When you open an image of any format in an editor, the program will "adapt" to that image, but any changes made are going to be program specific and will most certainly change the original if it is overwritten.
Some programs do not store previous work when saving. You'll want to check that aspect before you overwrite the original image. I suspect that you won't be overwriting the RAW image, just that you want to maintain a workflow for the current iteration.