Hi, if you play on MAC, some files will be hidden. To access your save files:
Finder > Locations > Users > your user tag > Here is where you'll have to make your hidden files to appear, so click cmd + shift + "." and the hidden files will appear > Library > Application Support > Pokemon Reborn > your saves will all be there.
For some reason, Pokemon Reborn on MAC doesn't recognise multiple save files, so you'll have to change your save file's name to the one that's being used: For example, if you save your game and the last save file you have is under "Game_2.rxdata", if you want to use an old save file, you'll have to name it "Game_2.rxdata"
Hope it helps!