You can change your delivery window until your order cutoff time (cutoff visible under your Order Details).
On goodeggs.com, go to Your Orders page. Click on Order Details > for your active order. On the next page, click the Change button in the Delivery Time section.
In the Good Eggs iOS app, click on the Market tab at the left bottom corner. You'll see a green banner for your upcoming delivery. Click on this banner and then click Edit Order on the next page. Tap directly on the current delay window and edit your delivery window from there.
Please note, at this time, there is no way to change the delivery day for an existing order. You will need to cancel your existing order and create a new order for the desired day. We'd recommend placing the new order first to make sure that it includes everything you'd like to order!