4GL 4.0 Updating Fields

Currently, I am trying to do a "batch" update of exising records within a table. For example if my table contains the following records: KEY | FIELD 1 1 | NO 2 | NO | | NO | | NO 100 | NO I would like to read in a flat file consisting of KEY and FIELD 1 to update FIELD 1 from NO to YES. i.e. 1|YES 2|YES 3|YES | | etc. Is there a utility that allows you to update? I believe that LOAD only adds to the table. I just want to update specific fields in existing records. Thank you in advance.