This page details how to delete your current save in order to start a new one in Pokemon Omega Ruby & Alpha Sapphire.
Step 1: Watch or skip the opening cutscene as usual.
Then on the title screen, press B, X, and Up and the D-Pad simultaneously.

Step 2: You will then be prompted to delete your current save. Select “Yes”.

Step 3: You will need to confirm the action one more time. Select “Yes” again to delete your save.
Note: Doing so will delete your current save permanently, with no way of recovering it.

Step 4: After deleting your saved data, you will be taken back to the language selection screen to start a new game.
