Quicken Bill Pay offers the two following options to change a payment:
Through the Web:
Note: After a payment has started processing, you can no longer make changes to it. A payment has started processing if the payment status is anything other than Scheduled (for example, In Process or Processed). If you overpaid the amount, contact the payee to request a refund or a credit toward your next payment. If you have been charged late fees, contact the payee. They may waive the fees for you.
In your Quicken software: If a payment is Sent, you can cancel the payment if it is more than two business days before the scheduled payment date. If it is a check payment, you can cancel the payment if it is more than four business days before the scheduled payment date.