Nintendo Switch Manual page 73

Deregistration process
1. Go to Nintendo eShop on the HOME Menu, then
select the appropriate user.
2. Select the user icon ("Account Information") on
the top right of the screen. Go to active console
for downloads and select "Deregister" to
deregister the console.
Registering another console as the active console
for downloads
Link your Nintendo Account to a user on the
console. Then, access Nintendo eShop with that
user to automatically register the console as the
active console for downloads for that Nintendo
Account. Once the console is registered, you will
need to redownload the Nintendo Switch
software you purchased using that Nintendo
Account.