Short answer. There is a separate law for that. Article 2237 provides that insolvency shall be governed by special laws insofar as they are not inconsistent with the Civil Code. The Civil Code sets the general backdrop, particularly on preference of credits, but the insolvency process itself is handled elsewhere.
What the law says
Insolvency shall be governed by special laws insofar as they are not inconsistent with this Code.
Civil Code, Article 2237 — Insolvency Governed by Special Laws. Read the full provision →
The Civil Code hands the subject off deliberately
Article 2237 is short, but it settles exactly the question you are asking. Insolvency shall be governed by special laws insofar as they are not inconsistent with this Code. The Civil Code does not attempt to lay out the full procedure for a debtor surrendering assets to creditors, appointing an assignee, or otherwise formally going through insolvency — it defers that entire subject to legislation written specifically to handle it.
What 'not inconsistent with this Code' actually means
The deferral is not unconditional. Special insolvency laws govern only to the extent they do not conflict with the Civil Code itself. Where a special law and the Civil Code genuinely clash on a point the Civil Code has already addressed, the Civil Code's own provisions are not simply displaced by the special law's mere existence. In practice, though, this article mainly clears the way for procedural and substantive insolvency rules to operate as their own coherent framework rather than being read as somehow already covered by the Civil Code.
Where the Civil Code still matters in an insolvent estate
This deferral does not mean the Civil Code has nothing to say once insolvency is underway. The Code's own provisions on preference of credits, for example, come into play specifically when a debtor's assets are not enough to satisfy everyone owed — that framework works alongside, not instead of, whatever special insolvency law governs the process itself. The two bodies of law are meant to operate together, each covering the part it was written for.
What this means for your situation
If your debtor wants to formally surrender assets through an insolvency process, the specific procedure, forms, and court involved are matters for the special law that governs insolvency, not something this article or the rest of the Civil Code spells out directly. This page cannot tell you the filing steps or timelines, since Article 2237 itself does not contain them — it only confirms that a separate law, not the Civil Code, is where that procedure actually lives. Knowing that distinction at least tells you where to direct your search, and where your debtor's obligations under this article end and the special law's procedural requirements begin.