Sistema de recuperación de evaluaciones pendientes

Sistema de recuperación de evaluaciones pendientes
 

How can we say this in English?
This is more or less, a system or some rules or theory that establishes, how sb who failed a subject in a term or even the previous year, I mean the steps to follow to give them the opportunity to pass the subject.

This sounds like 'remedial testing'.

If a student has missed examinations, or classes, s/he takes remedial testing or remedial classes to make them up.

it is when they have failed the subject.

Same.