Hi there, Sandi!
It sounds like your client doesn't have a learning management system (LMS), so you're using a Rise 360 course to act as a learning portal, is that right?
While Rise 360 aren't designed to function as a learning portal where you can grant and revoke user access, you may want to check out Rise.com!
Rise.com is an all-in-one online training system that gives you one place to create, track, manage, and analyze training. It includes all the authoring functionality from Rise 360, plus the ability to enroll learners, track their progress, and analyze training effectiveness—all in one place. If a colleague leaves the organization, you can easily remove their access to Rise.com.
To see it in action, head over to rise.com! You can also email the Rise team at sales@rise.com.