Managing the subscriptions that you have contracted using your Apple ID is not only possible from a computer or from a device with iOS, but there is another device that you must add to the list and that from it, especially the last generations, is also possible manage these hires. Exact, we mean Apple TV.
Before starting with the little tutorial, we must tell you that this is only possible to do it directly from the device, when it comes to the fourth generation Apple TV or the Apple TV 4K; in case of being the third generation Apple TV or earlier, you will have to manage, yes or yes, everything from iTunes on the Mac or from an iOS device. With that said, let's continue:
The first thing you should find out is if the service you want to manage - giving the same reason (cancel, increase, renew, etc.) -, is if this service has been contracted from your Apple ID; if you did it from the Apple TV or on the contrary everything it is through other means. What should you do now? Once inside the Apple TV menu, go to "Settings" and then click on "Account"; that is, something similar to what we were telling you if we do it from iTunes.
You will see that a new window opens and in it several sections appear, one of which corresponds to "Subscriptions". Click again and select the option "Manage subscriptions." Again you will be moved to a new window and it will be there where you will see all the current subscriptions at that precise moment. Choose the subscription you are interested in modifying or check —for knowing what is the date on which the service expires— and being able to renew, cancel, etc.
Remember in the last generations of Apple TV (4th generation and 4K) it is possible to download applications and many of them offer in-app purchases. All of them, if you hire them and have them installed on your Apple TV, they can be managed without the need to go to a third team.