Changing email address

I am a SAP user since the days of SDN and I have a user ID. I always used to login with the user ID and change my email address as and when I changed companies.I no longer can do that. i can create a new profile but then I will lose my history. How can I keep my history and yet be able to change email address? This is a genuine use case, people do change companies and cannot be expected to use the same email address.