To upgrade your Shared Hosting plan you need to -
1. Log in to your Client area account.
2. Go to My Services
3. Select your Shared Hosting Plan
4. You will see an arrow sign "→", click on it
5. You will get the Upgrade/Downgrade Option.
6. Select the plan you wish to upgrade upon with the needed billing cycle and click on continue.
7. It will provide you with the difference amount that needs to be paid. Pay it and your plan will be upgraded to the next level plan.