The Constitutional Court examines the constitutionality of a legal provision as applied in a specific case. It can declare the provision unconstitutional, or — far more commonly — declare it constitutional only when understood in a particular way, which is a form of binding reinterpretation. It cannot re-examine the evidence, reduce a sentence, or acquit anybody.
Where the Court rules in favour of the applicant, the practical consequence is that the applicant's case is subject to review by the ordinary courts. That is the mechanism by which a constitutional ruling turns into a changed sentence — indirectly, and through a further application.