The process of scheduling replacement classes is a crucial activity in a university environment. This task is performed when events occur that result in the cancellation of scheduled classes, such as a teacher's unavailability, emergency situations, and others. The manual approach to scheduling replacement classes often takes a long time, lacks efficiency, and is prone to errors. Therefore, an efficient system for scheduling replacement classes is needed. The Object-Oriented Analysis and Design (OOAD) methodology is used for the analysis, which includes various diagrams such as use case diagrams, use case scenarios, sequence diagrams, and activity diagrams.