Reset your network settings on a iPhone?

Hi, does anyone know what kind of password you should use for resetting your network settings, because first i thought you should use your Pin- code but I was wrong. I think that you maybe should use your apple-id password but I'm not sure and I don't want to risk taking the wrong code because I have failed two times and I think I have one try left. So if anyone knows which password you need to use please answer, and maybe there's a way to reset the settings using itunes? Please share your infomation about this cause I need help!

Look here

http://www.tuaw.com/2009/11/11/iphone-cellular-data-not-working-try-resetting-your-network-set/