How to Update a single column through informatica?

Question

I have a target table with the following attributes:

PARTY_ID PK
START_DATE PK
STATUS_CD PK
END_DATE

I have a dynamic lookup which is returning me 1(insert) 2(update) 0 (duplicate) for each row from source table.

What i want is when i get 2(update) to add an END_DATE to the updated row without changing anything else.

For example i have the following row in my target table:
1 12/01/2014 2 NULL

and i get this row from my source table:
1 14/01/2014 6 NULL

What i want is to add ONLY the end date to the target table without anything else. LIKE:
1 12/01/2014 2 14/01/2014

I know how to update the whole row but i dont know how to update only one column.

Schema:
CREATE SET TABLE IND_MAR_STATUS ,NO FALLBACK ,
 NO BEFORE JOURNAL,
 NO AFTER JOURNAL,
 CHECKSUM = DEFAULT,
 DEFAULT MERGEBLOCKRATIO
 (
  INDIVIDUAL_PARTY_ID DECIMAL(18,0) NOT NULL,
  INDIV_MARITAL_STAT_START_DTTM DATE FORMAT 'YYYY-MM-DD' NOT NULL,
  MARITAL_STATUS_CD VARCHAR(100) CHARACTER SET LATIN NOT CASESPECIFIC NOT NULL,
  INDIV_MARITAL_STAT_END_DTTM DATE FORMAT 'YYYY-MM-DD',
  ETL_SOURCE_ID DECIMAL(18,0) NOT NULL,
  ETL_EXTRACT_SPEC_ID DECIMAL(18,0),
  ETL_JOB_RUN_ID DECIMAL(18,0))
PRIMARY INDEX ( INDIVIDUAL_PARTY_ID );

Answer 1

Simply disconnect the target ports you don't want to update (i.e. only PARTY_ID and END_DATE should be connected).