Firstly, this thread is over 7 years old, so if you want to raise the subject again, you should start a new thread.

Secondly, you have missed the point, as the subject is how to change a dynamic IP address that your ISP has allocated to you. It wasn't made clear why you would want to do this, but I suppose you might if you were experiencing a DoS attack?

Hidemyass is a proxy service, so the sites you visit don't see your true IP address, but the one assigned to you by by Hidemyass. Your router/modem is still using IP address assigned by your ISP, so you haven't changed that.

The easiest way to change a dynamic IP is to power off the router and wait a few seconds. Alternatively you could disconnect the router from the gateway or phone/cable connection.

Obviously you are still traceable via your connection to your ISP, but if you were under attack, it would mean that the attacker would have to find you again.