#2 - Feb. 4, 2010, 5:46 a.m.
Each Authentication Key is good for the creation of one, and only one, account, Dillen. If you would like to make a secondary account for your daughter, then you would have to purchase a new account. You may do so by starting a trial account and upgrading it, utilizing the Recruit-a-Friend program, purchasing the game from your local retailer, or purchasing the game using the Blizzard Store.
*Please note that if you use the online upgrade feature, or Blizzard Store there are a few minor restrictions in place until your financial institution clears the transaction. These restrictions are to protect against fraud and will be removed once payment verification is fully complete; this may take up to 72 hours.
Once you have the Authentication Key, regardless of how you come about them, you will be able to create the account within your already existent Battle.Net account. To do so, first log in to Battle.net Account Management, and then go to the Manage My Games section. From there, select Add a World of Warcraft Account and follow the steps to permanently link a World of Warcraft account to the Battle.net account.
After you log in to World of Warcraft using the Battle.net Account, you will be prompted to select which of the merged World of Warcraft accounts you wish to play. Players with multiple World of Warcraft accounts are still able to log in and play them simultaneously. Just be aware that you will need the Authenticator for either account tied to your Battle.Net account.