How to set array element to null value

[Brahmam Eswar]

I'm trying to reset array element to null. but 3rd line of below snippet is
giving the compilation error.


FOR indx_1 IN array_lower(X, 1)..array_upper(X, 1) LOOP
IF X[indx_1].REFERENCE_VALUE = 'ABC' THEN
X[indx_1].REFERENCE_VALUE:='';
END IF;
END LOOP;

-- 
Thanks & Regards,
Brahmeswara Rao J.