You have a whole backend order management system at your disposal. This is called “Search Orders”. This is a powerful tool that gives you full access to your orders and allows you to do customer support on the fly. You can easily look up orders from any event, old or new. When searching, it is best to use an order number if available. The next best thing is to use either Last Name or last 4 digits of credit card used since those can be more unique than a first name. Once you find your customer you will have all the abilities you need to help them out.