Our name-change process is as follows:
- User submits the name-change form to HR.
- HR processes the form, entering it into our automation systems.
- Automation systems spit out an extract containing the 'address book' information for all active counts, the fields include among others:
- The account management system takes the extracts and updates fields wherever they've changed. When it gets to this user, it changes the first/last name as needed.
- When the user is ready for the email change they notify the helpdesk.
- The helpdesk hits a button in our account management page that makes the new first.last@ mail address the Reply-To to address for that account. All old email addresses are retained on the account.
The key thing here is that when a name changes (with on the order of 4000 people, this happens frequently) we just change their display data. We do not generate a new account. If their userID was smithk (Karen Smith), we won't change it to barnesk (Karen Barnes) if they change their last name. If a user presses the issue, hard, we will generate a completely new set of accounts for them, but it takes a lot of pressure to get us to do that. Because of this, if their name changes they don't get a completely new mail account, it's the same account just with a different name on the To and From lines.
In your case what I would do is this:
- Export the old mailbox to PST
- Import the PST to their new mailbox
- Add the old email address as an additional SMTP address to the new mailbox
- Delete the old mailbox
You may have to temporarily increase their mail quota to accommodate the PST import, then let them do the cleaning before you drop it again.