Follow the steps below if you would like to edit an order:
1) From the left menu, select Orders. This will bring you to the New tab, where you can view all of your pending/new orders.
2) Go to the more (...) icon, which is located right next to the Ship Now button, and click on it.
3) You can edit shipment's weight & dimensions, payment mode, pickup address, and customer's details. 
4) Once the information has been modified, click the Update button to apply the changes.