You can copy an existing file to a different location in your S3 bucket. User who initiates a copy operation should have read permission on the copy source file.

```dart
import 'package:amplify_flutter/amplify_flutter.dart';

Future<void> copyGuestFileToPrivate({
  required String sourceKey,
  required String destinationKey,
}) async {
  try {
    final result = await Amplify.Storage.copy(
      source: StorageItemWithAccessLevel(
        storageItem: StorageItem(key: sourceKey),
        accessLevel: StorageAccessLevel.guest,
      ),
      destination: StorageItemWithAccessLevel(
        storageItem: StorageItem(key: destinationKey),
        accessLevel: StorageAccessLevel.private,
      ),
    ).result;

    safePrint('Copied file: ${result.copiedItem.key}');
  } on StorageException catch (e) {
    safePrint('Error copying file: ${e.message}');
    rethrow;
  }
}
```