@SammyS welcome to myoozic.com family. You are at the right place to learn music!
1. Before changing scale of a song you need to identify the current scale (or the key note of the song) that the song is set.
follow this thread to learn more on this:
http://myoozic.com/threads/chords-of-a-song-how-to-identify.21762/#post-27324
2. Once you have identified the Key of the song, you can transpose the song to different key to create entirely new song. You will have to use 'Audacity software' for this. Please google to get more information on how to transpose songs in Audacitly. Believe me, it's easy.