Changing your IP address can end a DDoS attack (at least temporarily). When requesting a new IP address from your provider, make sure you also send a DHCP release or renewal request as part of the process. Otherwise, you may receive the same IP address you had before.
Also, if you use a dynamic DNS service and the attack is directed at your hostname instead of the IP address, you may find that you are still under attack, as the hostname follows you to your new IP address.