```kotlin
import io.appwrite.Client
import io.appwrite.coroutines.CoroutineCallback
import io.appwrite.services.Databases

val client = Client()
    .setEndpoint("https://<REGION>.cloud.appwrite.io/v1") // Your API Endpoint
    .setProject("<YOUR_PROJECT_ID>") // Your project ID
    .setKey("<YOUR_API_KEY>") // Your secret API key

val databases = Databases(client)

val response = databases.updateDocuments(
    databaseId = "<DATABASE_ID>",
    collectionId = "<COLLECTION_ID>",
    data = mapOf(
        "username" to "walter.obrien",
        "email" to "walter.obrien@example.com",
        "fullName" to "Walter O'Brien",
        "age" to 33,
        "isAdmin" to false
    ), // optional
    queries = listOf(), // optional
    transactionId = "<TRANSACTION_ID>" // optional
)
```