Use the following steps to change the Default SMS app to the app of your choice.
Setting the default app
1. Tap Settings.
2. Select Apps & Notifications > Advanced.
3. Tap Default apps.
4. Tap SMS app > select the app you would like as your default SMS app.
5. A popup window will appear letting you know to reboot and unlock your device before the changes will take place, select Ok.
Note: The selected app will manage, receive and send all your text messages.