Using CiviCRM 4.6.4 and Drupal 7.41, we have a large event set up with complex pricing (3000+ registrants each year, lots of price options). Folks forget to register for things the first time through, or they change their mind.
We haven't been able to determine a good way to process these people who need to edit their fee level choices. I can edit fee level choices just fine when there isn't any money involved, but don't see a good way to make a 'credit card 'edit' to a registration'.
To make it more difficult, we would prefer to turn 'multiple registers with same email' off, because we tend to have admin assistants and the like sign up many folks under one email and it takes a lot of staff time to sort that out.
The fee level choices must be accurate and held in a single event record (no dupes for the event) to print the correct badge onsite, so if we do need to submit a second registration we would have to create a new with all fee level choices and delete the old ones. This tends to cause the financial tally to be off and is a different admin headache, but this is the route we have taken for now.
Does anyone have a recommendation for processing these credit card edits without the admin headaches?