Customer cannot change his/her order once it has been processed in the system.
In order to modify the order, he/she needs to call the store. When that happens, you can amend the order on their behalf using Oddle Register iPad App.
1. Log into your Oddle Register iPad App and click the Pencil on the top right corner of the selected order to make amendments.
2. Follow the steps explained in Creating an Order via Oddle Register iPad App to make the required changes.
If you want to be more stringent about order amendments, you can include a term that says "no changes are allowed once orders are placed" in your policy or terms and conditions.