The NDF_ library does not allow you to re-write history. However, it does allow past history records to be deleted so that irrelevant information can be removed, usually to save space. The routine NDF_HPURG will perform this, as follows:
INTEGER IREC1, IREC2
...
CALL NDF_HPURG( INDF, IREC1, IREC2, STATUS )
Here, the history record numbers IREC1 and IREC2 specify a range of existing records to be deleted. Once these have been removed, any remaining records are re-numbered starting from 1.
It is recommended that users of NDF applications should normally invoke this routine via a utility application which records its own history information in the NDF. Thus, while the processing history may subsequently be incomplete, a record showing that deletion has occurred would still be present.