1.) Make sure you have a save on the game.Need for Speed- The Run (EU)(en,fr,de,it,es,nl).sav , seems is not possible
2.) Make a save backup of your game in checkpoint.
3.) Go to your 3ds's sd card and go to 3ds\checkpoint\backups [I think it is called backups] then find the folder for your game go into the backup folder and replace the .sav files with the completed .sav files