s 131 Recall of witnesses on trial of altered or new charge
131. If a charge is altered or a new charge is framed by the court after the start of a trial, the prosecutor and the accused must, on application to the court by either party, be allowed to recall or re‑summon and examine any witness who may have been examined, with reference to the altered or newly framed charge only, unless the court thinks that the application is frivolous or vexatious or is meant to cause delay or to frustrate justice.