Upgrade, downgrade auto-renewable subscription

Hello, Having two app versions: basic and premium. Both are with equal content but with different allowances. Basic version can do less than the premium version. When upgrading from basic to premium is the basic version on the mac deleted or is it still there but only disabled by the App Store? In the last case there are two subscriptions on the mac: one enabled the other disabled. If only subscription duration or price is upgraded or downgraded there is no problem involved because both have the same allowances. Thanks for any help or advice