gdgt

Well you can change it if you have the appropriate tool. But by saying appropriate i mean apple specific tools. Apple has very unique internal designs in their products in order to put everything in the smallest casing and there are a lot of intersecting elements unlike other electronics products. If you try to change it without prior knowledge and just by dismantling the elements trying to remember the order, it will not work and you'll probably damage something you don't mean to.

And don't forget that the profit of technical service is much higher than the actual profit from the sale of the product, so i'm pretty sure Apple guaranteed their products to get broken when someone other than the authorized staff tries to fix them. You should find the important tricks and needed materials to disassemble/assemble the electronics. I suggest you to give it to the technical service. That way you can save your MBP, unlike me who lost his MBP and Iphone 3G trying same thing :D