diff --git a/services/voiceinteraction/java/com/android/server/voiceinteraction/DatabaseHelper.java b/services/voiceinteraction/java/com/android/server/voiceinteraction/DatabaseHelper.java
index 4a8623db066bc..bed85fc46b6c1 100644
--- a/services/voiceinteraction/java/com/android/server/voiceinteraction/DatabaseHelper.java
+++ b/services/voiceinteraction/java/com/android/server/voiceinteraction/DatabaseHelper.java
@@ -94,7 +94,7 @@ public class DatabaseHelper extends SQLiteOpenHelper {
     }
 
     public boolean addOrUpdateKeyphraseSoundModel(KeyphraseSoundModel soundModel) {
-        SQLiteDatabase db = this.getWritableDatabase();
+        SQLiteDatabase db = getWritableDatabase();
         ContentValues values = new ContentValues();
         // Generate a random ID for the model.
         values.put(SoundModelContract.KEY_ID, soundModel.uuid.toString());
@@ -105,7 +105,7 @@ public class DatabaseHelper extends SQLiteOpenHelper {
         if (db.insertWithOnConflict(
                 SoundModelContract.TABLE, null, values, SQLiteDatabase.CONFLICT_REPLACE) != -1) {
             for (Keyphrase keyphrase : soundModel.keyphrases) {
-                status &= addKeyphrase(soundModel.uuid, keyphrase);
+                status &= addOrUpdateKeyphrase(soundModel.uuid, keyphrase);
             }
             return status;
         } else {
@@ -114,18 +114,16 @@ public class DatabaseHelper extends SQLiteOpenHelper {
         }
     }
 
-    /**
-     * TODO(sansid): Change to addOrUpdate to handle changes here.
-     */
-    private boolean addKeyphrase(UUID modelId, Keyphrase keyphrase) {
-        SQLiteDatabase db = this.getWritableDatabase();
+    private boolean addOrUpdateKeyphrase(UUID modelId, Keyphrase keyphrase) {
+        SQLiteDatabase db = getWritableDatabase();
         ContentValues values = new ContentValues();
         values.put(KeyphraseContract.KEY_ID, keyphrase.id);
         values.put(KeyphraseContract.KEY_RECOGNITION_MODES, keyphrase.recognitionModeFlags);
-        values.put(KeyphraseContract.KEY_SOUND_MODEL_ID, keyphrase.id);
+        values.put(KeyphraseContract.KEY_SOUND_MODEL_ID, modelId.toString());
         values.put(KeyphraseContract.KEY_HINT_TEXT, keyphrase.hintText);
         values.put(KeyphraseContract.KEY_LOCALE, keyphrase.locale);
-        if (db.insert(KeyphraseContract.TABLE, null, values) != -1) {
+        if (db.insertWithOnConflict(
+                KeyphraseContract.TABLE, null, values, SQLiteDatabase.CONFLICT_REPLACE) != -1) {
             return true;
         } else {
             Slog.w(TAG, "Failed to persist keyphrase to database");
@@ -133,6 +131,26 @@ public class DatabaseHelper extends SQLiteOpenHelper {
         }
     }
 
+    /**
+     * Deletes the sound model and associated keyphrases.
+     */
+    public boolean deleteKeyphraseSoundModel(UUID uuid) {
+        SQLiteDatabase db = getWritableDatabase();
+        String modelId = uuid.toString();
+        String soundModelClause = SoundModelContract.KEY_ID + "=" + modelId;
+        boolean status = true;
+        if (db.delete(SoundModelContract.TABLE, soundModelClause, null) == 0) {
+            Slog.w(TAG, "No sound models deleted from the database");
+            status = false;
+        }
+        String keyphraseClause = KeyphraseContract.KEY_SOUND_MODEL_ID + "=" + modelId;
+        if (db.delete(KeyphraseContract.TABLE, keyphraseClause, null) == 0) {
+            Slog.w(TAG, "No keyphrases deleted from the database");
+            status = false;
+        }
+        return status;
+    }
+
     /**
      * Lists all the keyphrase sound models currently registered with the system.
      */
diff --git a/services/voiceinteraction/java/com/android/server/voiceinteraction/VoiceInteractionManagerService.java b/services/voiceinteraction/java/com/android/server/voiceinteraction/VoiceInteractionManagerService.java
index 7204695039db7..63702ba2f76b1 100644
--- a/services/voiceinteraction/java/com/android/server/voiceinteraction/VoiceInteractionManagerService.java
+++ b/services/voiceinteraction/java/com/android/server/voiceinteraction/VoiceInteractionManagerService.java
@@ -281,12 +281,25 @@ public class VoiceInteractionManagerService extends SystemService {
                     throw new SecurityException("Caller does not hold the permission "
                             + Manifest.permission.MANAGE_VOICE_KEYPHRASES);
                 }
+                if (model == null) {
+                    throw new IllegalArgumentException("Model must not be null");
+                }
+
                 final long caller = Binder.clearCallingIdentity();
                 try {
-                    if (mDbHelper.addOrUpdateKeyphraseSoundModel(model)) {
-                        return STATUS_OK;
+                    // If the keyphrases are not present in the model, delete the model.
+                    if (model.keyphrases == null) {
+                        if (mDbHelper.deleteKeyphraseSoundModel(model.uuid)) {
+                            return STATUS_OK;
+                        } else {
+                            return STATUS_ERROR;
+                        }
                     } else {
-                        return STATUS_ERROR;
+                        if (mDbHelper.addOrUpdateKeyphraseSoundModel(model)) {
+                            return STATUS_OK;
+                        } else {
+                            return STATUS_ERROR;
+                        }
                     }
                 } finally {
                     Binder.restoreCallingIdentity(caller);