Upgrading account from Pro to Business

[MaraAlex-83]

The Learning Center says: "You can upgrade your Zoom plan at any time. If you upgrade in the middle of the billing period, the account will be credited a pro-rated amount for the time remaining on your existing subscription and you will be charged for the upgrade with the credit applied."

But it is not clear what subscription period will be provided? a year? or before the expiration date of the previous plan?

How will the payment be considered?