Not sure if this can be done per slide, but If all the pages contain 2 slides, splitting pages in half may work for you.
Most probably, the "slides" on the pages are imported images. Depending on which method was used to create the pdf, a software might help you to extract the images. You could then print the images one-per-page as pdf.
In Linux, this could be
pdfimages from the
poppler-utils package or
On Windows, you could either screenshot the images, or, as an example, install
imagemagick and also use
Edit: if all that still does not output images (e. g. because the slides are all Powerpoint shapes), I'd try to use a screenshot tool which helps me to automate the process.
Picpick (for Windows), for example, can be set to screenshot the same area across multiple captures. So I'd set this up for the first slide, scroll to the next and hit PicPick's short key for screen capture.
Another alternative which comes to my mind for a scenario, where the slides are Powerpoint shapes is an image editor which can open pdfs, e. g.
Irfanview with the pdf plugin. Open the pdf in that image editor and save it as a series of images. I'd go with bmp, png or tiff if the quality of the later images is important. After that, you have a series of images with two slides on each of them. Run
imagemagick on them to extract the single images.