For anyone wondering if you can change Kids to adult, OAP to adult etc, you can. Once they are in your basket, you select the drop down box and select which age group you want.
says this on the q&a page on Wednesday website
Using your friends and family ID numbers.
Please note that many supporters have shared ID numbers with others in the past. Please do not book a ticket under family or friends IDs unless they are fully aware that you are doing so. Once an ID number is used it cannot be used again.