I use below beta Java SDK.

<artifactId>microsoft-graph-beta</artifactId>
<version>6.4.0</version>

I want to update existing attributes(identity here).

        GraphServiceClient graphClient = new GraphServiceClient(_clientSecretCredential,
                    new String[] { "https://graph.microsoft.com/.default" });

        ...

        String filter = String.format("identities/any(c:c/issuer eq '%s' and c/issuerAssignedId eq '%s')", issuer, issuerAssignedId); 
        
        User user = graphClient
                .users()
                .get(requestConfig -> {
                    requestConfig.queryParameters.filter = filter;
                })
                .getValue().get(0);

        for (ObjectIdentity identity: user.getIdentities()) {

            if(identity.getIssuerAssignedId().equalsIgnoreCase(issuerAssignedId)){
        
                System.out.println("original issuerAssignedId = " + issuerAssignedId + " new issuerAssignedId = " + newIssuerAssignedId);
                identity.setIssuerAssignedId(newIssuerAssignedId);
            }
        }

But I don’t see any patch() method in UsersRequestBuilder.java. How can I patch user?