MSIR.0423 Cannot change CENTSPAN/SPANSIZE on SIRFIELD (subcmd) command because ERROR or ALTERNATES have been set and records have been added to the file

This message indicates that a SIRFIELD 'subcmd' command was issued with the CENTSPAN or SPANSIZE clause, and the ERROR or ALTERNATES formats, or both, have been set for the field. Since records have been added to the file, allowing a different CENTSPAN or SPANSIZE could cause previous values matched by one format to now be matched by a different format, which might change the data, for example when you reorganize the file.

The command is rejected.