PostgreSQL:

ALTER OPERATOR

ALTER OPERATOR name ( { left_type | NONE } , { right_type | NONE } )
OWNER TO { new_owner | CURRENT_USER | SESSION_USER }
ALTER OPERATOR name ( { left_type | NONE } , { right_type | NONE } )
SET SCHEMA new_schema
ALTER OPERATOR name ( { left_type | NONE } , { right_type | NONE } )
SET ( { RESTRICT = { res_proc | NONE }
| JOIN = { join_proc | NONE }
} [, ... ] )

Example

ALTER OPERATOR @@ (text, text) OWNER TO joe;
ALTER OPERATOR && (_int4, _int4) SET (RESTRICT = _int_contsel,
JOIN = _int_contjoinsel);