The current IEP Manager is able to reassign the student to a new IEP Manager.
Navigate to the student's “Forms Menu”, click on “Student Sharing” and then the “Send this student to a new case manager” button.
Select the new IEP Manager from the drop down list and click “Send” (put a check in the “Reset current student sharing” checkbox if you no longer need access to this student, if you leave it unchecked you will continue to have edit access to this student).