Ayodele Ayoola said it...you can also create child themes, this may be a better option for you.
also themes may update themselves, wiping out your hard work, check this post out or this one
good luck and happy learning curves ;)
Question
Sorry if my tune is not good!
I want to change the name of wordpress theme "Twenty Twelve" to "iBlast".
Problem:
When I rename it from "Wordpress->wp-content->theme->Twenty Twelve" directory. It display in dashboard as "Twenty Twelve/iBlast". But it should display just "iBlast", not "Twenty Twelve/iBlast".
Solution
Ayodele Ayoola said it...you can also create child themes, this may be a better option for you.
also themes may update themselves, wiping out your hard work, check this post out or this one
good luck and happy learning curves ;)
OTHER TIPS
To change it you'll need to edit the style.css file in the base directory of the theme.