It would be very helpful, if the content of the communication would change, too. E.g., if Sandy's new name is Jeeves, instead of starting a line with "Sandy, remember..." to address the assistant, it should be "Jeeves, remember...".
Matching the part before the @ in the changed email address would be a quick shot.
Being able to exchange the picture of Sandy/Jeeves/MightyLordOfDoom would be another nice touch.