Lennie Jarratt wrote:

Is there an easy way to change a user's password or delete the user without affecting any page changes they have made?

You can use the changepassword.php script in the maintenance directory. Rather than delete the user, I just rename them to something like "Deleted User". If they've done anything, revisions show them as Deleted User and I can see the original name in the database's real name field.

Mike