I created 2 Subscribe button with paypal. This buttons for different membership : 1. basic 2. pro. I am trying to subscribe membership with thisbuttons and working without any problem. But when I was trying to upgrade or downgrade via other buttons paypal create new membership. So If I use 2 buttons for membership I have 2 active membership: pro and basic on paypal. How can I prevent this?
Use "modify" variable in the subscription button, so that the existing subscription will get modify and there will be only one subscription. Click here for more information.