You have two options here. You can keep the same name and give the course a new version, or you can rename the course. In either case, the newly uploaded course, with a new version or name, will not overwrite the existing version on the web server. Those students who are currently in the process of taking the current version of this course will continue to see only this older version, i.e., they will see none of the changes in the new version.
If you use groups to assign courses to students, the students will not even see this new version of the course until you assign it to a group containing the students that you want to see this new course version.