Swapping videos on YouTube
No, you can't. You can use the built-in features of the platform such as adding cards or applying 'Enhancements' (Youtube's terminology, not mine), but there's no way to replace the video itself. From the official documentation: 


  You can’t replace a video because any new video you upload to YouTube
  will get a new URL. Instead, you can make changes to an existing
  video: 
  
  
  Enhance your video: You can make some editorial changes to the video using YouTube Video Enhancements. You can trim parts of your
  video, auto-fix lighting and color, blur parts of the video, apply a
  filter, and more.
  Add cards to your video: You can use cards to change elements of your videos. You can point viewers to a specific URL (from a list of
  eligible sites) and show customized images, titles, and calls to
  action, depending on the card type. 
  Change your video's title and description: You can organize and make changes to your video's title, category, description, and privacy
  settings.
  


If video replacement is a feature you deem necessary for whatever content you are producing, you might consider switching to a hosting platform that allows you to do this. For example, replacing the original video file while keeping views, comments et c. intact is possible on Vimeo (documentation, as of August 2017).