To disconnect a funding source, log in to your account and access the account settings page. The steps are the same whether your have a bank account or debit card connected to your account.
STEP 1: Click the 3 dots on the right-hand side and choose "Delete."
STEP 2: Confirm by selecting "Delete" again.
(NOTE: You'll need to go through the same connection process as before in order to add or reconnect a funding source. Follow these links for help with connecting a bank account or debit card.)