If you want to remove your Slack integration with Mention, please follow these steps:
1. Manage your Slack apps
Select the Manage apps option into your Slack app window. You can click on your personal menu, then Administrations and finally Manage apps.
2. Delete your Slack authorizations
You will access a Slack page that lets you delete your Slack authorizations. So you can click on the Remove configuration button.
That's all!
Don't hesitate to set new integrations in the future if needed!