Section 77Omnibus Election Code of the Philippines (Batas Pambansa Blg. 881), Sec. 77

Candidates in case of death, disqualification or withdrawal of another. - If after the last day for the filing of certificates of candidacy, an official candidate of a registered or accredited political party dies, withdraws or is disqualified for any cause, only a person belonging to, and certified by, the same political party may file a certificate of candidacy to replace the candidate who died, withdrew or was disqualified. The substitute candidate nominated by the political party concerned may file his certificate of candidacy for the office affected in accordance with the preceding sections not later than mid-day of the day of the election.

If the death, withdrawal or disqualification should occur between the day before the election and mid-day of election day, said certificate may be filed with any board of election inspectors in the political subdivision where he is a candidate, or, in the case of candidates to be voted for by the entire electorate of the country, with the Commission.