The dummy data would look like below. Basically only Person_ID and var1 need to be populated (as from data have to data want), but not var3 or var4 even thought they have missing values as well.
data have; infile datalines truncover dsd; input Person_ID var1 $ var2 $ var3 $ var4; datalines; ID,var1,var2,var3,var4 1,aa,aa1,aaa, ,,aa2,,10 2,bb,bb,bbb,6 3,cc,cc,ccc,8 4,dd,dd,ddd, 5,ee,ee,eee,7 6,ff,ff,fff, 7,gg,gg1,ggg,3 ,,gg2,,5 ,,gg3,,6 8,hh,hh1,hhh, ,,hh2,, ,,hh3,, ; run;
data want; infile datalines truncover dsd; input Person_ID var1 $ var2 $ var3 $ var4; datalines; 1,aa,aa1,aaa, 1,aa,aa2,,10 2,bb,bb,bbb,6 3,cc,cc,ccc,8 4,dd,dd,ddd, 5,ee,ee,eee,7 6,ff,ff,fff, 7,gg,gg1,ggg,3 7,gg,gg2,,5 7,gg,gg3,,6 8,hh,hh1,hhh, 8,hh,hh2,, 8,hh,hh3,, ; run;
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