using RETAIN to keep the previous value is useful here to make the logic fairly simple. data have; input account month Rel $ Pmt $; datalines; 1 201211 R O 1 201212 R P 1 201301 R P 1 201302 R O 1 201303 T P 1 201304 T O 1 201305 R O 1 201306 R O 1 201307 R P 1 201308 R O 2 201302 R O 2 201303 R O 2 201304 T P 2 201305 R P 2 201306 T P 2 201307 R P 2 201308 R O 2 201309 R O 2 201310 R P 2 201311 R P 3 201305 R O 3 201306 T O 3 201307 R P 3 201308 T P 3 201309 R O ; run; data want; set have; by account month; retain flag; if first.account then flag=0; flag=(rel='R' and (pmt='P' or flag=1)); if flag=1 then do;   drop flag;   output; end; run; ... View more

There are many ways to reorder variables in a dataset (a simple Google search will give you these), the important thing to note is that you need to replace the existing dataset (i.e. you can't just change the descriptor portion in something like PROC DATASETS). My favourite method is to use the RETAIN statement before you read in the data, this way you don't need to know any of the variable attributes (type, length etc), just the names). Here is an example data class; retain sex age height weight name; set sashelp.class; run; ... View more