Once your project receives its final validation, you can’t edit your rewards any longer.
You can always access the details of each reward from your project page by clicking the “Edit my content” link in project edition navigation bar, and then on “Rewards”.
If you wish to edit, add or delete a reward while the campaign is active, you need to get in touch with your success manager.
When creating your campaign, you have full control over the rewards (See Adding rewards)