Turn on the Nintendo 3DS
Open System Settings
Tap Data Management
Tap Nintendo 3DS
Tap Software
Select the game you want to delete
Tap Delete
Confirm the deletion
Repeat for any other games you want to remove
Turn on the Nintendo 3DS
Open System Settings
Tap Data Management
Tap Nintendo 3DS
Tap Software
Select the game you want to delete
Tap Delete
Confirm the deletion
Repeat for any other games you want to remove