If you need to change what tickets someone has ordered then this currently isn't directly possible. For this we recommend cancelling the order and putting through a new order with the updated quantities.
If you need to make a change the details of an order such as their name, email or some other information they supplied when purchasing, simply follow these steps:
Click Orders from the main navigation.
Search for the order using the tools available. You could search by name, email or ticket code.
Once you have located the order, click on it and you should see details of the order pop up.
Click the Edit order button and you should see a form where you can make any changes you need.
Click Save changes when you are done.