Here is good use of a merge without by.

    data a;
        input id var;
    datalines;
    1 1
    2 2
    3 3
    ;
    data b;
        set a end=last;
        _n_+1;
        if last then call missing(var);
        else set a(keep=var) point=_n_;
    run;

data b;
  merge a a(firstobs=2 keep=var rename=(var=var2));
run;

proc print;run;