First, open the local.xml configuration file in your favorite text editor, or use the Text Editor in the cPanel File Manager. The file is usually located in the app/etc/ directory under your Magento installation. Locate the following code segment:
Now, replace admin with your new admin path. This should be something personal which is hard to guess, use only letters or numbers - no special characters, then save the file.
The final step is to refresh your cache. Use an FTP client to delete the content of the var/cache/ directory, or use the following SSH command.
(First, navigate to you Magento root directory)