You can change your current membership plan anytime. Login your membership and visit the UPGRADE PLAN tab. Checkout with the new plan you want to subscribe to. That’s it.
Upgrading or downgrading your current plan will be pro-rated, so you will not be over-charged. To view previous payments, you can visit your Profile and access the Billing tab to see all payment history.
You can also change plans doing the following…
Login your account and go to Profile > Account
Then select Change and choose the plan you’re wanting!