Changing Title

I was not sure where I should post this.
If you create your website using a local host and name it XYZStoreAndMagazine and before you bring it live onto your site, you decided you need to change the name because you bought a different domain ABCMagazineAndShopping.com. Clearly, I will have a couple of different plugins and maybe a couple of different themes. How big of a deal is this? How many things will need to be changed? Or is there a plugin that will make the changes for me, throughout?