Hi Saud,
I'm not sure if it is a good idea to share the code... when I said it's quick-and-dirty, it means exactly that 
Essentially all I do is look at the table /PERSOS/FLAVSYS and swap the SYSTEMID field of flavors to match the current (target) system's ID from table /PERSOS/SYSCONID.
It's safer to do such changes manually in the admin transaction.
Tamas.