It is of course great if you can sell the PRO function to your customers.
For this, we have added this in the point of sale.
First make sure that the option 'Automatically make all new members PRO' in the System Settings > Portal content, is turned off.
Then go to System Settings > Point of Sale > add product > advanced options > select: PRO membership.
This way you can easily sell the PRO membership to your customers.
You can of course also add this in your webshop, so that your clients can purchase this themselves.