How do I let my members upgrade or downgrade their account?
If you want to provide a form to allow an existing member to upgrade (or downgrade) their account, please use the Billing Modification Forms, e.g., s2Member → Stripe Pro-Forms → Stripe Billing Modification Forms
We suggest creating a new, member-only page called "Upgrade/Downgrade" that includes one or more of these forms to allow your existing member to upgrade/downgrade their account.
Keep in mind that you can also use the Checkout Options feature here to show a drop-down that lets a member choose which form they want to use; see s2Member → Stripe Pro-Forms → Stripe Wrapping Multiple Shortcodes as 'Checkout Options'. This would allow you to have a single form on the Upgrade/Downgrade page that let's the member choose what they want to to do.