The initial idea was to create new accounts and end-date the old accounts in Oracle eBS. However, it turns out that you can rename them by making use of the change_user_name function which can be found in the fnd_user_pkg package in the database.
The example Amar is using on his weblog is the example below:
begin fnd_user_pkg.change_user_name( x_old_user_name => 'AMARKP', x_new_user_name => 'AMAR.PADHI' ); commit; end; /Without much effort you could create a script to mass update all the users that are in need of an update. You do most likely would like to add some reporting, logging and notification to this script to make it robust however the use of fnd_user_pkg.change_user_name will play a central role.