Can a judge set aside a prior judgment and enter a different ruling?

In Nacht v. Nacht, 167 Cal.App.2d 254, at page 265, 334 P.2d 275, at page 282, wherein a final decree of divorce nunc pro tunc was entered, the court said: 'Can the judge, by merely declaring that a prior ruling was entered inadvertently, set that ruling aside and enter a different ruling? Will the appellate court, based on such a declaration alone conclusively presume that the change in mind occurred prior to the entry of the first order? We think not. The sanctity of judicial pronouncements cannot be made to depend on such insecure foundations. Once made, a judicial pronouncement cannot be set aside except as provided by law. Certainly it cannot be set aside by [200 Cal.App.2d 592] the judge who pronounced it simply changing his mind on the law or the facts. If a prior judgment or order is to be set aside there must be something more in the record to support the order than the mere declaration of the trial judge that the prior order was entered inadvertently. The court had no legal power to correct a judicial error in this fashion.'