Administrators use the Admin interface to perform administrative tasks, such as configuring the system, defining the CR process, installing process packages, setting up users, creating lifecycles, installing packages, modifying list box values, and more.
See Getting started: Administrators and Administering Rational Change
Through the User interface, users can create and modify change requests (CRs).
See Getting started: Users and Managing change and releases using Rational Change
The ReportBuilder interface to design reports that contain all the information needed to track CRs, tasks, and objects. This feature is available in the User and Admin interfaces when you log on and have ReportBuilder privileges.