Short answer. The title stays the same as in the trial court. Rule 124, Section 1 provides that in criminal cases appealed to the Court of Appeals, the appealing party is called the appellant and the other party the appellee, but the title of the case remains as it was in the court of origin.
What the law says
In all criminal cases appealed to the Court of Appeals, the party appealing the case shall be called the "appellant" and the adverse party the "appellee," but the title of the case shall remain as it was in the court of origin.
Rule 124, Section 1 — Title of the case. Read the full provision →
New labels for the parties
Section 1 introduces appellate terminology once a criminal case reaches the Court of Appeals: whoever is appealing becomes the 'appellant,' and the other side becomes the 'appellee.' These labels replace the trial-level references to prosecution and accused for purposes of identifying who is asking for what on appeal. This labeling convention applies regardless of which side — prosecution or accused — happens to be the one seeking appellate review in a given case. These labels do not change who bears the burden of proof or any substantive right on appeal; they are purely a naming convention for identifying roles in the appellate pleadings, not a substitute for the underlying prosecution-versus-accused relationship the case still rests on.
But the case caption itself does not change
Despite that shift in party labels, the rule is explicit that the title of the case shall remain as it was in the court of origin — meaning the caption still reads 'People of the Philippines versus [accused's name],' regardless of which side actually filed the appeal. That consistency is what allows the appellate record to be matched cleanly back to the trial court docket and case file it came from. This binds the clerks and lawyers preparing the appellate record just as much as the parties themselves; a caption that drops the original title in favor of 'appellant versus appellee' would defeat the very purpose Section 1 is trying to serve, which is easy cross-referencing back to the case's origin.
Why this distinction is kept
Keeping the original title preserves continuity and makes the case easy to trace back to its trial court record, while the appellant/appellee labels serve the practical purpose of identifying roles within the appellate briefs and proceedings themselves. The two conventions serve different functions and Section 1 keeps them separate rather than letting one override the other. This binds anyone preparing appellate pleadings — captions must still read 'People of the Philippines versus [accused's name]' on every filing, even though the body of a brief or motion may freely refer to the parties as appellant and appellee throughout.