We normally sell extra items separately as well as in packages, so you can add them easily at a later date. For example, we sell accommodation separately for most festivals - so if you have already booked tickets, you can make a new order for a hotel only. Take a look on Festicket.com for the festival you are going to, and order extra items as you want.
If you can't book the new item by itself, but we do have it for sale on Festicket, send us a message with your existing order number and what you'd like to add. We'll do our best to help.