As the needs and requirements for a NetBackup environment change, it may be necessary to migrate the NetBackup catalog information from one Master Server or platform to another or to combine two or more NetBackup domains to form a single domain.
While migration and merging is possible, NetBackup Support does not have the necessary resources and experience to properly execute this process. NetBackup Support can assist in restoring the data back to the same original platform in the event of a failed attempt, but is not equipped to assist in these sorts of activities. To insure data integrity and seamless operation, operations of this type must be performed by Symantec Consulting Services.
(more at)
http://support.veritas.com/docs/267137