You would have to first add a secondary bank account on the bank page on Kuvera. Once added, you can drop a message to support@kuvera.in with details of the bank account that you want to remove from your Kuvera account.
Do Note: Removing a bank account from Kuvera will not update the bank details in existing folios with respective AMCs. You will have to submit a bank change request to the respective AMC/RTA for updating bank details in existing folios.