The super administrator account automatically has permission to switch to a different person or login as a different person. This functionality can also be granted to other administrators as well. There are three places where you have access to switch to a different person.
NAE Lookup Screen
When you are looking up a person record via the NAE lookup screen, in the lookup results under Action, there is a link called Switch To User (figure 1).
View NAE Record
The second location is in the left sidebar when viewing a name and address record (figure 2).
The third place is via the student header (figure 3). When you are viewing any type of student record, you will be able to see the Switch To link.