PowerPoint 4:3 slide show on 16:9 screen

Hi, when a 4:3 slide show is viewed on a 16:9 screen it makes the canvas left and right of the slides black - is there a way to make this white, so it matches the slide's background? Much like viewing a 16:9 slide on a 4:3 puts the black canvas above and below the slide. I've looked everywhere and only find the obvious, how to change the slide background colour - not the canvas (or screen outside the slide). I'm guessing there's no VBA for this, but got my fingers crossed. Thank you

It cannot be changed. The idea is to not show the cut off areas when the slide is projected I think, whatever, black is the only option.