[Zope] Renamed user account and OpenFlow

[Tit-Liviu Leontin]

Hello everyone,
 
I'm currently taking over the administration of a running instance of Zope and OpenFlow. These have been used to create a workflow for a decision making process. The users are authenticated via LDAP.
 
The problem is, one of the workflow users got married and the username has been changed to reflect the new last name. Instances already in the workflow are assigned to the old username, and the person cannot log in to interact with them. I can assign the new username to the correct role, but what about the old instances?
 
Is there an easy way of migrating the instances assigned to the old username to the new one, or maybe creating a local user with the old username? Any step-by-step suggestion is welcome, as I'm barely getting familiar with the admin interface.
 
Thanks in advance,
Titel