Partial loss of object of obligation
Article 1264 of the Civil Code provides:
ART. 1264. The courts shall determine whether, under the circumstances, the partial loss of the object of the obligation is so important as to extinguish the obligation. (n)The courts will determine if the partial loss of the thing due is so important that it would constitute the extinguishment of an obligation. Partial loss is present when only a portion of the thing is loss or destroyed or when it suffers depreciation or deterioration.[1] For example, X obliged himself to dance for Y in his birthday. A day before Y's birthday, X was injured making it hard for him to dance. Here, the partial loss is equivalent to a complete or total loss. It is so important as to extinguishing the obligation.
[1] De Leon. (2014). Obligations and Contracts.