MSIR.0349 New CENTSPAN/SPANSIZE ((cspan1)/(spansz1)) does not fully contain old values ((cspan2)/(spansz2))

This message indicates that a SIRFIELD FORMAT command was issued with the CENTSPAN or SPANSIZE keywords, and that the command could not succeed because the resulting valid range of dates does not contain all of the valid dates previously established for the field.

The valid range of dates of a two-digit year field is from the (effective) CENTSPAN for a period of years equal to SPANSIZE. A SIRFIELD FORMAT command may:

1. increase SPANSIZE, up to its limit of 100
2. decrease the effective CENTSPAN, but the same command must increase SPANSIZE by the amount that CENTSPAN is being decreased

These changes allow you to increase, but not "shift", the range of valid dates established for a field. Any other changes to CENTSPAN or SPANSIZE are not allowed. 

If you wish to "shift" the range of dates, you must re-INITIALIZE the file, change the CENTSPAN and/or SPANSIZE values on the earlier SIRFIELD FORMAT commands which included the dates you wish to "shift out", and re-execute the series of SIRFIELD commands for the file. 

The command is rejected.