You can upgrade, downgrade or cross-grade your subscriptions using a Switch subscription. If you have purchased your subscription on monthly basis then you can upgrade to a yearly basis or vice versa using the Switch subscription option.
The subscription can be classified in one of the three categories based on pricing:
If you switch from a $1000 / month subscription to a $1500 / year product, the price for the next subscription is higher. As a result, it may appear to be an upgrade. However, if you only remained subscribed to the $1500 / year subscription for one week and then switched to a different subscription which is less than the value you would have consumed, and remained subscribed to the subscription with the lower price. As a result, the switch to the new subscription considered as a downgrade.