What do I need to change a black iPhone 4 to a white one?

My dad is really good with mechanics and God knows what else, but I asked him to replace my phone to a white one if I payed for it. He said he would but all the conversion kits were so expensive! I planned to buy everything separate off Amazon. Everything on my phone works just fine I just wanted to change the color. What all do I need? Keep in mind that I already bought a back and just the front glass. Do I need to order a new LCD Digitizer? Or would I be able to use my old one?

They can change the case color in the mall near my house for $75

Just purchase a white case for you iphone from any mobile accesories shop and they will install it to
or just visit the link below
https://www.google.com.pk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCkQtwIwAA&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D9vUiWNlRpjI&ei=R3bYUtzlKI-c0wXKq4DoAg&usg=AFQjCNGQ4fSVshDUOxUOglfxGZ52ZecWLg&bvm=bv.59568121, d.d2k