Moving wordpress subdirectory to root

I know this has been answered but I’m still not getting this to work.

I had a wordpress site here: kanya-z.com/iconstudio

I successfully moved it to a new server here: http://icontattoostudio.com/icontattoo2014

and now I want the wordpress to be the main domain of icontattoostudio.com

Everytime I try to change the site url in general settings the site gets reverted back to my server kanya-z.com/iconstudio

What is the easiest way to do this that will work?
Thanks!