To leave a quota of a student of the school to zero we must accede to:
Planning → Sport school → Courses/Schools.
Once we have entered, we will click on the icon in the school where we want to leave the account of a student to zero:
Now we will access the section Payments Control and we will see the list of payments of the school:
To leave a quota of a student of the school to zero we will click the icon and the quota will disappear from the listing.