The judge may increase the sentence, lower it, or refuse to interfere with what the trial judge ordered.
With respect to verdict appeals, the judge can:
Decide not to hear the appeal;
Hear the appeal and dismiss it;
Substitute a conviction on a lesser offense (and probably reduce the sentence);
Direct that the offender be acquitted; or
Order a new trial.
Mennonite Central Committee Canada. (2011). Getting through the maze: A guidebook for survivors of homicide.