Use Word to copy the document to a new location and then rename. If you want to save a copy of your document, but then make changes to it later. You should save separately, and this will create two different documents. You cannot save anything more than one place at one time.
When you save a word document, it automatically saves in the word program. Then, go back and choose "save as," and then type the name of the document and save. Any time you want to make changes to a document, you should always save it.