Yes you can cancel without penalty unless some are the ones that require a CC charge. Then you must cancel within a certain time frame before the meal to get the credit put back on your card. The ones that come to mind are CRT and some of the dinner shows like HDDR and Mickey's Backyard Bar B Q.
Even those can be cancelled but there is some time frame like either 24 or 48 hours ahead of time I think if you want your money back. They charge you when you make the reservation for these not when you show up. I think that even if you have the
DDP you are charged and then credited back when you show up for the reservation.