Short answer. The civil registrar and everyone who has or claims any interest that would be affected by the correction must be made parties to the proceeding. This judicial requirement applies to substantial corrections; purely clerical errors can instead go through the administrative route with the local civil registrar.
What the law says
When cancellation or correction of an entry in the civil register is sought, the civil registrar and all persons who have or claim any interest which would be affected thereby shall be made parties to the proceeding.
Rule 108, Section 3 — Parties. Read the full provision →
The civil registrar is always a required party
The rule names the civil registrar as a required party in every case covered by this provision. Since the registrar's own records are what the petition seeks to change, their participation in the proceeding is not optional — it is built into the rule itself, regardless of who else may also need to be included as well.
Omitting the registrar from a petition of this kind is a defect that can undermine the entire proceeding.
Anyone with an affected interest must also be joined
Beyond the registrar, the rule requires all persons who have or claim any interest which would be affected thereby to be made parties. This is a broad standard: it is not limited to the person whose entry is being corrected, but reaches anyone else whose own interest could genuinely be affected by the outcome of the correction actually being sought.
This joinder requirement applies to the judicial route specifically
This rule governs the judicial proceeding for substantial corrections to a civil registry entry. RA 9048, as amended by RA 10172, opened a separate administrative route through the local civil registrar for purely clerical or typographical errors, a change of first name, and the day, month, and sex entry where the error is clerical — those administrative corrections do not go through this joinder requirement at all.
Confusing the two routes can lead someone to pursue a full judicial proceeding, with all the parties this rule requires, for a correction that could have been handled far more simply and cheaply through the registrar instead.
Why proper joinder matters in a Rule 108 petition
Failing to include everyone whose interest is genuinely affected by a proposed correction can leave the resulting order vulnerable to later challenge by someone who was never given a real chance to be heard. A petitioner should identify, before filing, everyone with a real stake in the entry being corrected or cancelled — not just the civil registrar, but any other person whose recorded interest the change would actually touch or affect.