If, after initial registration is closed, you need to make changes to your registrations and/or add/delete students/registrations, you will have to use the Change Requests online tool found when you login to CDLI. This tool allows you to do make a registration request and monitor its progress until it is completed.
Login to your CDLI account and click on the Change Requests link on the right hand side of the page.

You should see the following:

Click the Add Student(s) tab. You should see the following:

Select the Course, Student, Slot and please include Additional Notes explaining the details of the request.
Click the Drop Student(s) tab. You should see the following:

Select the Course, Student and please include Additional Notes explaining the reason for the drop.
Click the Transfer Student(s) tab. You should see the following:

Select the From Course, To Course, Student, Slot and please include Additional Notes explaining the reason for the transfer.