This article provides a straightforward description of why you have to convert and includes a link to quickly convert. You get to choose a new IM account name and MS converts the account in about an hour the article states. Essentially, once the conversion takes place and your contacts login again, their contact for you is converted to the new account. There is no disruption. We have found that sometimes when the person converts and then logs in with the new user account, even a day later, all of their contacts appear offline. Reboots and attempting to login with the corpdomain.com account do not work.
MSN support recommends:
- Log in to MSN messenger with new account name.
- Export your contacts to a file (Option in Menus)
- Delete all your contacts manually
- Import the contacts file.