I won't go into details about why we need to do this, but:
We are going to be disconnecting about 5000 Exchange Mailboxes from their associated AD accounts, because those AD accounts will now be associated with email accounts that don't live on our Exchange server.
As for the disconnected mailboxes, we want to create NEW AD accounts for them, and connect the mailboxes to them. The new accounts will have the same usernames, except with something appended to end of them (for example 'user' will now be 'user_temp', 'user1' will now be 'user1_temp'). I've been reading up on how to do a mass reconnect of mailboxes, but everything I've seen looks like it tries to match the username, which will nolonger be the same. I'm not sure if there's a way to script doing this so it looks for the new username? Or, make it so it'll create new usernames for these dead mailboxes based on criteria I specify?