In order to do this you will need to cancel your current VIP.  You can do this at any point.  You will retain your VIP privileges until the end of your billing cycle.  At that point your account goes back to a basic member.  Then after your current VIP expires you can upgrade again with CCBill by using the online sign-up form locate at:
http://secure.redlightce....com/upgrade/upgrade.asp

As for canceling your current subscription with CCBill, RLC Support can do it for you at any point you wish by contacting us at support@redlightcenter.com or by visiting our Support page: http://support.redlightcenter.com/support.asp

You can also downgrade with CCBill's Support which is available 24/7 at: https://support.ccbill.com/