In ruling on such motion, in a cause tried without a jury, the court may, on such terms as may be just, change or add to the statement of decision, modify the judgment, in whole or in part, vacate the judgment, in whole or in part, and grant a new trial on all or part of the issues, or, in lieu of granting a new trial, may vacate and set aside the statement of decision and judgment and reopen the case for further proceedings and the introduction of additional evidence with the same effect as if the case had been reopened after the submission thereof and before a decision had been filed or judgment rendered. Any judgment thereafter entered shall be subject to the provisions of sections 657 and 659.