If the email address is linked to a closed or canceled account you can install the 'deleted records manager' module and delete it using that module. If it is an active account you will need to use a different email account. The purpose of this is so that people can not create multiple accounts with the same email (possible spammers) and also to ensure that the password reset feature sends the proper information to the correct email account. You can imagine the problems for password recovery if accounts used the same email...
Something to look into would be to require email AND username in the password reset module. This would then allow for using the same email multiple times on different accounts. Could make this an admin selected choice to allow/disallow multiple accounts with same email. Me.B (future feature?)
Something to look into would be to require email AND username in the password reset module. This would then allow for using the same email multiple times on different accounts. Could make this an admin selected choice to allow/disallow multiple accounts with same email. Me.B (future feature?)