CLearnLesson::RelationRemove

static function RelationRemove ($parentLessonId, $childLessonId)
{
	self::PublishProhibitionPurge_OnBeforeRelationRemove ($parentLessonId, $parentLessonId);
	CLearnGraphRelation::Unlink ($parentLessonId, $childLessonId);
	CLearnCacheOfLessonTreeComponent::MarkAsDirty();

	BitrixLearningIntegrationSearch::indexLesson($parentLessonId);
	BitrixLearningIntegrationSearch::indexLesson($childLessonId);
}