Here's how:

1. Log in to your PayPal account.
2. Click Settings near the top of the page.
3. Click Payments.
4. Click Manage pre-approved payments.
5. Click Cancel or Cancel automatic billing and follow the instructions.

If you don’t have a PayPal account, you should contact the merchant directly to cancel the agreement. 

If you can’t contact the merchant, you should contact PayPal Customer Service by phone. Here’s how:

1. Go to the PayPal website.
2. Click Help at the top of the page.
3. Click Call customer support.
4. Click You can always Call us as a Guest.

Please note that after canceling a payment, subscription, or automatic billing agreement, you are still required to pay the merchant for the goods or services you received. A subscription can be cancelled up until the day before the next scheduled payment in order for you not to be charged.