If a field within a record in an externally described file is to
be renamed, enter the external name of the field in these positions.
A field may have to be renamed because the name is the same as a
field name specified in the program and two different names are required.
If the input field is for a file that has
the PREFIX keyword coded, and the prefixed name has already been specified
in the Field Name entry (positions 49 - 62) of a prior Input specification
for the same record, then the prefixed name must be used as the external
name. For more information, see
PREFIX(prefix{:nbr_of_char_replaced}).