If you're an existing customer and you simply want to switch your existing payment method to PayPal you will need to do the following:
1. Remove the existing payment method(s) from your account, log into the Customer Control Panel with your main account's username and password.
2. Click Account Tab.
3. Click Payment Methods
4. Click the Payment Method
5. Click Delete.
6. Once your subscription is up for renewal you will log into the Customer Control Panel with your main account's username and password.
7. Click Account Tab
8. Click Subscriptions
9. Click your subscription
10. Click Renew Subscription
11. Select the Billing Period Duration, Click Next
12. Select PayPal Express under Payment Method.
13. Click Place Order and complete the on-screen instructions to login to your PayPal account and authorize the billing.