Many apps want the server to be able to update a wallet. For example, an app might want to update the policies or signers on a wallet, even with the user offline. For server-side wallet updates, Privy generally recommends:
1

Create a wallet with a 1-of-k key quorum

Create your wallet with a 1-of-k key quorum, whose members include at least a user and an authorization key controlled by your server. You can do this via Privy’s REST API.
2

Update the wallet with your authorization key

As a satisfying member of the key quorum that owns the wallet, your server’s authorization key can unilaterally update the policies and additional signers assigned to the wallet. This enables your app to update wallet configurations, even when users are offline.