The present is a system and method for preserving user account security privileges during a migration or re-direction of data from one network attached storage (“NAS”) system to another. Certain NAS systems authenticate user accounts using Kerberos Delegation Technology. In addition, some NAS systems feature the ability to constrain delegation to certain services. While effective in limiting access and promoting network security, this constrained delegation restricts the ability of a storage virtualization system to migrate or re-direct data to other NAS systems, especially if the other NAS system resides or is identified by a different domain name. The present invention is a system and method for storing user account credentials that work with the former NAS system, and providing a way to translate these credentials to a new NAS system with a new domain, permitting seamless data migration and re-direction across domains.