If you want to delete a bank account you've already connected, simply open the app menu, go to "Manage your accounts", and you'll have the option to remove the connected account there. If you're using the mobile app, slide the connected account to the left to delete your connected account.
Note - if you don't have a bank account connected, you will no longer qualify for double pay for every survey, and we may not be able to invite you to other surveys we're running.