To upgrade your hosting plan, follow a simple procedure.
Login to your customer area, select, in "My services" section, the plan you want to upgrade and then click on "Manage";
In the following page, click on "Improve hosting plan";
Now, choose your new service, select the billing cycle and confirm your order clicking on "Buy".
You will be redirected to your cart to check the cost of the new plan. Here, you can choose your method of payment. Click on "Complete your order" to end the operation.
The upgrade of your shared hosting will be instant, automatic and available after the payment.