This is useful in case you want to activate a new device, but you have reached the activation limit for the type of device.
You can only deactivate your Sony home entertainment device on a PC/Mac connected to the internet.
You cannot deactivate it using a PlayStation 4, PlayStation 3, PS Vita, PS TV, PSP or onthe device itself.
You can reach Account Management in a number of ways:
Tap [PlayStation Store] on the home screen and go to [Online ID] > [Account Settings].
Go to PlayStation Store. Sign in, go to your Online ID at the top of the page and click [Account Settings].