Many organizations allow students to make up a missed class. If your database is set to track absences you will have the option to offer a makeup class to a student who was absent. When a student absence is entered, and the absence is marked eligible for makeup, a makeup class can be scheduled at that time or it can be scheduled at a later date.
From the Tools menu > Edit Settings > Student Settings you can Always Allow Makeups, Never Allow Makeups or Select (eligibility) with Each Absence.
Watch a (1:06) video tutorial on Scheduling Class Makeups