Once a campaign has been created and launched, it is not possible for you to update your rewards directly in the RewardStream Portal.
We recommend creating a new campaign with your new rewards. You can copy the landing page, email, and share message content from your previous campaign and update the content to reflect the new reward. Once you've done that, you can make that new campaign the Default Campaign. All referrals made in the previous campaign will continue to process as expect and all new referral will be made with the new campaign with the updated reward.