How do i perform a factory unlock on my iphone 4 so i can use it on any carrier

Unlock your apple iphone 4 and use any other carriers sim card
To unlock your apple iphone to use any sim card, you need to get the unlocked confirmation from apple by using any unlock code service provider.After getting the unlock confirmation you need to use i-tune to unlock it
here is the direct link of service provider to get the unlocked confirmation
How to unlock iPhone Factory Unlock iPhone

After getting the unlock confirmation you need to use i-tune to unlock it as below:-
How to Unlock the Apple iPhone 6 after getting the confirmation as Unlocked -

-Install the last version of iTunes on your computer.
-Make sure your iPhone 6 is updated with the lastest version of iOS.
-Switch ON your iPhone 6 with a SIM Card from a non-compatible network.
-Connect your iPhone 6 to your computer using the Original USB Cable.
-Launch iTunes andwait until iTunes detect your iPhone 6.
-Now disconnect your iPhone 6sand reconnect it after 10 seconds.
-Your iPhone 6 is now Unlocked!

Note:-In the unlikely event that your iPhone 6s is not unlocked, please restore your device following the official guideline from Apple - https://support.apple.com/en-us/HT201252

iPhones can only be unlocked through Apple. There are many people who will perform this for you, sometimes for about £15.00. I'd recommend you start with your carrier.

Contact the original carrier and see if youre illegible and they will take you from there!

You would have to contact your carrier to see if they offer a unlock service. After the carrier has confirmed that your phone has been unlocked, you can replace the SIM cards with the card of the other carrier.
If you would like a link to explain the process in more detail :
How to unlock your iPhone for use with another carrier
It may take a few days for the carrier to process the request.
Best of luck!

Locked iPhones can only be unlocked by the carrier they are locked to. Apple will not get involved. You need to contact he carrier and negotiate unlocking with them.

You can unlock your Apple iPhone 4 from carrier lock easily by using Remote Unlocking Service.To get this service at low cost visit the site Prounlocking.com here you need to specify the IMEI number of your phone,Country,Network provider to which it is locked.After unlocking from carrier lock,you can use any GSM network SIM card on your mobile.This is the safe,easy and permanent unlocking method.

If your iPhone 4 has been purchased before January 26 2013, You can visit www.TheUnlockArena.Com to get the remote unlocking service for your iPhone 4. This method of unlocking is safe, simple, affordable and quick. This method of unlocking doesn't require a jailbreak too.
If your iPhone 4 has been purchased after January 26th of 2013, You cannot unlock the device without the carrier's permission. As it has been declared illegal to unlock mobile phones without carrier's permission in USA.
To rescind this decision You can sign the online petition from https://petitions.whitehouse.gov/petitio... . Good luck mate.

An iPhone 4 can be unlocked safer and easier through remote unlocking method. It is also an affordable method too. You can get the remote unlocking for an iPhone from www.simpleunlocking.com all the best mate.

Remote I-phone Unlock service is best to Unlock IPhone 4 from network lock...You can get the Remote Unlock service at Superunlockcodes.com and Unlock it from network lock.