Banks require us to finalize payments at 3pm CT the business day before the payment is scheduled. At that point, we won't be able to make changes to the payment and it will show as processing in our system.
Due to your bank's internal practices, you may see your payment leave your bank account the business day before its scheduled. For example: Payments scheduled for Monday (or Tuesday, if Monday is a holiday) are submitted for processing at 3pm CT on Friday.