Date:         Fri, 10 Nov 2006 09:59:36 -0500
Reply-To:     souga soga <souga1234@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         souga soga <souga1234@GMAIL.COM>
Subject:      modifying data
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi,

I have a dataset

ID1    ID2
A001
A002  A001
A003  A002
F001
F002  F001
F003  F002


If ID1 gets modified then the original ID1
is placed in the ID2 variable in the next observation.
I need to track all the modified ID1's and replace them
with the original ID1.

expected output:

ID1
A001
A001
A001

F001
F001
F001

Thanks as always,

Sa