Talk:SAVE/@comment-129.22.151.42-20150930182141/@comment-5020614-20151202013454

I don't believe he can SAVE, he lacks the determination that Frisk and Flowey have to do so, however while he isn't able to SAVE and LOAD into other timelines like us, I think he is able to manipulate his presence in the timeline he is currently in, so he can appear in two places at once (potentially as a result of the fatal experiment that ripped apart Gaster), and his general intellect and his knowledge of the timelines, in tandem with his own astute observational skills allows him to figure out when someone is messing about with time travel, though he needs confirmation to be sure (such as his codewords).

So basically, no, Sans is unable to SAVE, but he's the last living individual to possess such  knowledge about the SAVE function without possessing the determination to actually use it.