You may code it as a function call.

proc iml;

a=shape(1:25,5,5);
n=nrow(a);
***remove R3C3****;
%let k=3;
idx1=cusum( &k || j(1,n-1,5) );
idx2=((&k-1)*n+1):&k*n;


b=shape(remove(a,idx1||idx2),n-1,n-1);
print  idx1 idx2 ;
print  a ;
print  b ;
quit;