how to combine two variables data into two rows in SAS

We have three variables in sas dataset and we want to create a new variable which would have values transposed for 2 variables and the third remain as it is.

Eg:

Acct_nb repl_acct_nb amount
12334 45678 100
23456 . 200

Output needed:
new_acct_nb amount
12334 100
45678 100
23456 200

>Solution :

I think this is what you want. Since, it is only 2 variables, no need for array logic.

data have;
input Acct_nb repl_acct_nb amount;
datalines;
12334 45678 100 
23456 .     200 
;

data want(keep =  new_acct_nb amount);
   set have;
   new_acct_nb = Acct_nb;
   if new_acct_nb then output;
   new_acct_nb = repl_acct_nb;
   if new_acct_nb then output;
run;