Purchasing a second copy of Elite Dangerous on your Frontier account will not give you access to a second commander.
If you would like to have more than one commander you will first need to make a new Frontier Store account with a different email address from your first account. After you have created your second Frontier Store account, log into it through the Frontier Store and purchase the content you'd like to access
Once this purchase has been confirmed, use the Elite Dangerous launcher to log into the new account. If you are already logged in to the Elite Dangerous launcher you will need to log out of your main account first via the Options menu.
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