Sometimes composers recreate their own song by adding a different orchestration and in some cases the new version sounds even better than the original. A few such examples are:
Prathidhinam Nee Darsanam (Anumanaspadham): This is a recreation of the Tamil song Mayanginen Solla Thayanginen and was used in the Telugu movie Anumanaspadham by Ilaiyaraja. The newer version sounds better owing to the updated orchestration, another worthy addition being the nice alaap after the first paragraph by Shreya Ghoshal. Unnikrishnan and Shreya do a very good job with the singing.
Saara Yeh Aalam (Shiva): This is the recreation of the famous Tamil song Aanandha Raagam Ketkum Neram from Panneer Pushpangal, sung by Uma Ramanan. The Hindi version becomes a duet song and is sung very well by Roop Kumar Rathod and Shreya Ghoshal. The strings-based orchestration sounds more grand and powerful.