How to unlock an iPhone 4 on Orange?

I bought an Orange locked iPhone a year ago contract free and put my orange sim in and I'd like to unlock it now for resale; does anybody know how to get it unlocked by Orange?

Go to apple

There may be chances to unlock your IPhone4 from your network provider(orange). If they denied you can approach third party online services. To which country orange network your Iphone4 is locked to. If it is locked with Israel orange network you can unlock your Iphone4 here http://www.onlinegsmunlock.com/apple-iphone-4/rs16wp9/. Here they unlock your Iphone4 using remote unlocking method.