Plan change behavior
Both plans must be in the same Plan Group for customers to change plans themselves through the portal. Free-to-paid changes require a new checkout — the customer is redirected to complete payment.
An immediate upgrade is rejected with a seat-limit error when the customer’s current seats exceed the target plan’s included seats for a seat feature that is not unlimited and has overage disabled. Reduce seats first, or pick a plan with enough included seats. Interval-only changes and scheduled downgrades are not affected.
If you need to expand features or limits temporarily without changing the subscription’s plan, price, or billing cycle, use a Plan Grant instead.