Nintendo Switch Manual page 72

2. Select the user icon ("Account Information") on
the top right of the screen. Go to "active console
for downloads" and check whether the console is
active.
Deregistering the console
If you would like to register a different console as
the active console for downloads for a Nintendo
Account, you must first deregister the current
console.
This process can only be done using the active
console itself. Furthermore, if a console is
deregistered from a Nintendo Account, any
software purchased using that Nintendo Account
will no longer be playable on the console.
Software purchased using a Nintendo Account can
be redownloaded on a console by registering that
console as the active console for downloads for
the Nintendo Account.