There is a portlet on the student home page of the portal that shows a student his or her time to register, whether they have any business office holds that will keep them from registering, and reminding them to have their advisor clear them for registration.
If you need to know how an advisor clears an advisee, that's on the “Advising” page of the “Advising and Registration” tab. You would need to search for students with an advisee status of "needs registration clearance" for that semester. The "registration clearance" column will be displayed, and a "grant" button will appear for students needing to be granted clearance to register.
Advisors can't clear business office holds. The student can take care of those in the business office. If a student doesn't appear at all among the list of students who should be able to register for fall classes (perhaps because CX thinks they are going to graduate - I'm not sure if CX tries to distinguish between expected graduates and expected returners), a problem like that would have to be sorted out by the registrar's office.
Tags: Portal (my.carthage), registration