```dart
import 'package:appwrite/appwrite.dart';
import 'package:appwrite/permission.dart';
import 'package:appwrite/role.dart';

Client client = Client()
    .setEndpoint('https://<REGION>.cloud.appwrite.io/v1') // Your API Endpoint
    .setProject('<YOUR_PROJECT_ID>'); // Your project ID

Presences presences = Presences(client);

Presence result = await presences.update(
    presenceId: '<PRESENCE_ID>',
    status: '<STATUS>', // optional
    expiresAt: '2020-10-15T06:38:00.000+00:00', // optional
    metadata: {}, // optional
    permissions: [Permission.read(Role.any())], // optional
    purge: false, // optional
);
```