You would have to prove to the administration team that you are worthy of coming back, if you were caught scamming its a perma-ban for life unrevokable.

In order to get off a perma-ban by yourself, you'd more then likely have to hack into JaGeX's network in one way or another. That being highly unlikely, I'd say to stick with Tyler's answer or create a new account and deal with the fact that your old account is down for the count.

If we are talking about runescape would have to send them an email stating that why ever you were banned was no right, but if you were really at fault for doing something bad or wrong then just change your IP and make a new account

Whirlpool wrote If we are talking about runescape would have to send them an email stating that why ever you were banned was no right, but if you were really at fault for doing something bad or wrong then just change your IP and make a new account

Unless you were indeed hacking into JaGeX, I don't see a need for changing your IP. Unneeded step, they already took your account.