I know our users can edit certain fields of events they've registered for, but can the edit the QTY of registered for an event. Lets say they registered 4 people. One person cancelled, can they log into the portal and add or remove others in the group registration they registered for?
Unfortunately, it is complicated to handle and not supported by the extension. For example, what if removing member requiring refund? Same for adding member, that would require processing payment for that member....