This didn't help?
However, you can use the rpc call setaccount to change the account associated with the address. The first argument to setaccount should the the address you're changing; the second shound be the account you're moving it to. (If you want to move it to the default account, put "" as the second argument.)
Note that this does not change the balance of the account; balances are tracked internally. If you want to keep this consistent, run getreceivedbyaddress, then move that balance to the new account.
You can also use PyWallet to delete addresses permanently. Use the --multidelete option, and pass it a path to a file. That file should contain key as the first line, followed by each address you want to delete, each on a new line.
Nope. It doesn't delete the address and it didn't remove the address from my GUI. Besides, accounts are deprecated in Bitcoin Core.
I don't particularly care about this wallet so it doesn't matter that much to me if I delete the wallet and start over since I only use it for testing and armory. Although there are no coins in that wallet, I just want to avoid deleting it if possible.