Oftentimes during the order fulfillment process an expected delivery date will need to be updated. This can be due to stocking changes, carrier updates, or many other factors. Using Duoplane you can notify your end customer of any delivery date changes that need to be communicated.
First you can login and go to your order dashboard (https://app.duoplane.com/orders/dashboard) you can then click on the Promise date changes link. That will take you to the promise date alerts page (https://app.duoplane.com/promise_date_alerts) where you can trigger the email notification to the customer. You can customize what gets sent in the alert by going to Settings --> Ecommerce stores and selecting your store.