The trial court retains control over judgments during the thirty-day period after entry of judgment and may, after giving the parties an opportunity to be heard and for good cause, vacate, reopen, correct, amend, or modify its judgment within that time. Not later than thirty days after entry of judgment the court of its own initiative may order a new trial for any reason for which it might have granted a new trial on motion of a party, and every order granting a new trial shall specify the grounds therefor. After the filing of notice of appeal and before the filing of the record on appeal in the appellate court, the trial court, after the expiration of such thirty-day period, may still vacate, amend or modify its judgment upon stipulation of the parties accompanied by a withdrawal of the appeal.

The thirty-day period after entry of judgment for granting a new trial of the court’s own initiative is not shortened by the filing of a notice of appeal but is terminated when the record on appeal is filed in the appellate court.