Step 1 :
To change the theme of your published website, first you need to login to your account.
Then, go to 'Applications' from the sliding menu on the left of your screen. Then Click on START, just under 'Multi-screen website'.
Step 2 :
You arrive on the page where you can choose a new theme among the ones presented.
For this example, we can choose theme 2.
Step 3 :
Re-create your website according to the selected theme (you can go back to the tutorials 2.1. Create a new website).
The customization can be modified in the same way as your previous theme .
Once you finish creating your website, go to the configuration by clicking on "next " at the top-right.
You arrive then in the 'settings' for your domain.
Step 4 :
There you just have to select the option "I want to change the theme of one of my sites" , choose the site you want to replace and click on "next ".
==> Your new theme will be published as well !