Yes there's an option for reformating the memory, its an easy click and you'll erase all the data already on that wii except the updates it may have gotten. you can always change the name of the console without reformation or erasing the memory by going to that section in the settings
i did it accidentally once i wasn't paying attention so i freaked out and unplugged the wii. luckily only my virtual console games were deleted. if i had to restart all my games....omg i don't even want to think about it