Can I change my hosting plan?
You can upgrade the features of your plan whenever you want, but you cannot downgrade them until you are due to renew the service, as the payment is annual.
Change the hosting plan
If you already own a domain in your user account and are using a redirection & parking plan (free), you'll have to upgrade it to a hosting plan, to do so, go to My Domains (with your username & password), enter into the domain administration and at the Web Hosting tab press the Upgrade to bigger plan button.
Now you simply have to choose the desired hosting plan and make the payment of this upgrade in your shopping cart.