It was my understanding that undifferentiated records are *not* to be turned into differentiated records. Rather, when only one identity remains on the record, a new NAR will be created for that identity, and the undifferentiated record will be deleted. At least, that's the policy according to how I read DCM Z1 008/32.
Kevin M. Randall
Principal Serials Cataloger
Northwestern University Library
Proudly wearing the sensible shoes since 1978!