I would guess that you would invoke ....

Code:
DBMS_STATS.DELETE_COLUMN_STATS (
   ownname       VARCHAR2, 
   tabname       VARCHAR2, 
   colname       VARCHAR2, 
   partname      VARCHAR2 DEFAULT NULL,
   stattab       VARCHAR2 DEFAULT NULL, 
   statid        VARCHAR2 DEFAULT NULL,
   cascade_parts BOOLEAN  DEFAULT TRUE,
   statown       VARCHAR2 DEFAULT NULL,
   no_invalidate BOOLEAN DEFAULT FALSE);