How can i downgrade my blackberry from os 6 to os 5?

So a few weeks ago, i just got my blackberry bold 9650 and i love it. the phone can pre loaded with os 6 and i absolutely hate it. my friend has an older blackberry with os 5 and i think it is so much better. is there any way that i can downgrade my software from os 6 to os 5. i had never downloaded os 6 onto my phone, it just came like that. HELP!!