Promote another email catalogued as the one that identifies the account


Im trying to promote the current account that i have to github as a separate one for the company im working for. Ive set the primary email accordingly to the company email, but the original one that i was using werent liberated to create a new personal account. how should i proceed in this case? Is it really possible not just to replace the main contact email, but the email calagued at the user registration, and thus free it up for another account?