What if, in an exceptional situation, participants cannot make up their classes on a given date? You can grant them an additional impulse.
Go to Participants, then select the person you want to grant an additional impulse. At the bottom, you will find the Making up absences section. On the right-hand side, you will find a button called Grant additional impulse.
At the time of granting, select the date until which the impulse will be valid.