ACR recognizes that sometimes people make mistakes, and sometimes a player's profile of play changes dramatically. If you signed up for either Elite Benefits or rakeback and now want to move over to the other, this is allowed.
Be warned, however, that you can only swap between Elite Benefits and rakeback once over the lifetime of your account. Make sure that this is really what you wish to do, and then contact live chat from the ACR website or send an email to support[at]winningpokernetwork.com explaining your request. They will make the necessary adjustments to your account.