reg 46 Change of plea
(1) At any time before the court determines the finding, a defendant who has pleaded not guilty to the charge may withdraw his plea and substitute a plea of guilty. (2) But the court may not accept a plea of guilty substituted under paragraph (1) unless satisfied that the defendant understands the matters mentioned in rule 43(3). (3) At any time before the court passes sentence for an offence, a defendant who has pleaded guilty to the charge of the offence may, with the leave of the court, withdraw his plea and substitute a plea of not guilty. (4) Where a defendant changes his plea under paragraph (3)— (a) in the course of sentencing proceedings in relation to the offence, or (b) in the course of trial proceedings in relation to another charge, the court shall terminate the proceedings.