How can I adjust the number of pages shown per sheet WITHOUT printing?

I have several sets of lecture slides that are in landscape orientation, but instead of printing a bunch of full-size sheets in landscape orientation, I want to adjust my PDF so 2 landscape pages appear stacked on top of each other on a portrait page so when printed, each side of the page will have 2 smaller-scale slides for a total of 4 slides per double-sided sheet.

However, the only way I've found it's possible to change this setting is in the print settings, and there is no way to save the PDF instead of printing it. I've looked everywhere for an alternative but found no results. I need to be able to save the PDF instead of directly printing it because my university’s printing system requires that our files be uploaded to a specific printing website, so printing directly from Acrobat is not an option.