being naive I don't know how you do this. When my daughter was staying with me she decided to join AB and didn't want to use her own email account as it is for business only. She couldn't register using mine as it told her a user already existed with that email address.
I have a spare as I got banned for overposting. I just use bensmum2 as I don't feel the need to hide behind other names. I have 4 e-mail addresses for various things so just used a different one for the other name