What version of Premiere Elements and on what computer operating system is it running? Just in case we need to get into version specific matters.
Not sure if this is going to work, but consider using Premiere Elements' built in upload to YouTube feature as an example
Start the process, go through the authentication stage, until you get to the dialog that offers the Sign Out option. Sign Out and go through a Sign In process where I believe that you can Add Account and have the new account plus the default Account.
But, the path of least resistance would seem to be to export your Premiere ElementsTimeline content to a file saved to the computer hard drive and from there upload the file to YouTube, Facebook, or Vimeo using whatever account you want to.
Please review and consider, and let us know the outcome as your schedule permits.