That might not work if the new email address has to be validated. But might be worth a try.
Many forums don't really have a way to remove a member name from the forum as that goes somewhat with the forum having ownership of any post made by a member. Or at least I'm supposing it does.
If later SPAM is the only reason, then one might just create a rule in their email software to shunt messages from BF or containing a reference to BF off to their SPAM or some other folder or even delete it so they never have to encounter it. Though maybe not all email clients can do such.