Just like your computer systems use an operating system in the similar way mobile phones also use the same feature. If you want to get the operating system of your cell phones changed it is very easy. But it is better to change the version rather than changing to another OS so that warranty is preserved. Check whether your phone will be compatible with another version or not as some phones support only one type of OS.
Visit the official website of your phone and download the operating system or the higher version from there. Then run the application so that the OS gets installed in it. There are different kinds of OS which are supported by your phone so check completely before changing. Apart from changing you can also upgrade the version as the case may be. This will make your working on the mobile phone smooth and it can be used with the latest applications too.