If you switch subscription plans in the middle of a billing period, here's what happens:
If the new plan has a different billing frequency from the old plan (for example, monthly to yearly)
The first full period of the new plan begins immediately, and you are charged for the first period less the account balance.
If the new plan has the same billing frequency, we do something slightly more complex, but with the result of keeping the billing schedule the same:
We immediately create a line item for the remaining portion of the current billing period at the new plan rate.
At the next scheduled billing, the customer is charged for the line item and the full charge for the upcoming period, less the account balance.
If the account balance amount is larger than the amount due, you are not charged anything, and the account balance is carried over to future billing periods, until it's spent down.
We hope you find this helpful! If you need any further assistance, please contact us and we'll be more than glad to help you out.