First of all
Learn how to script, preferably in powershell since you're dealing with AD. Secondly learn how to build error trapping into your scripts. Thirdly you should already know how to script.
I've made this change in the past most often to align login names with email addresses to simplify life in a multi-userid age; more often now to disconnect userid's from email addy's due to security concerns.
Most of all - get a good policy that doesn't rely on random collections of initials and only apply to new/newish users. Always allow employees with lots of time at the company to keep their old ID's/email addy/phone number if at all possible - call it plank holders privilege.
Biting the hand that feeds IT
