Yes, you can.
1. Log in to your Amazon seller account and move to "Manage your apps" page.
2. Click the "Disable" button to cancel any authorization (MWS Auth Token and PPC Token) and disconnect to tool4seller.
To re-connect your seller account to tool4seller, please follow the steps on 2.2 How to Connect My Tool4seller to My Amazon Seller Account by MWS Auth Token.