SET data set if exists

[Patrick]

@Ronein Below one way to go.

libname r_r "%sysfunc(pathname(work))";
data r_r.panel;
  set sashelp.class;
run;

%macro backup(in=,backup=);
  %if %sysfunc(exist(&in,data)) or %sysfunc(exist(&in,view)) %then
    %do;
      proc datasets lib=%scan(work.&backup,1) nolist nowarn;
        delete %scan(&backup,-1);
        run;
        append
          base=&backup data=∈
        run;
      quit;
    %end;
%mend;
%backup(in=r_r.panel,backup=r_r.backup)

[AMSAS]

Example 1 in the exist function documenation can be changed to achieve what you want