Hi, Danielle! There are two different answers here for two different scenarios. First, there are a few dining experiences at Walt Disney World that require Guests to pre-pay for the meal upon booking, like dinner shows and Cinderella's Royal Table. Your card will be charged at that time. When you arrive for one of those meals, you can then utilize your Disney Dining Plan and get a refund. Simply tell the Cast Member serving you that you have a Dining Plan and want to use it instead of leaving the meal on your credit card. The Cast Member will deduct the Disney Dining Plan credits from your entitlements and refund your credit card. Make sure to bring that original credit card with you to the meal.
Second, most meals require you provide a credit card as a guarantee against being a no-show for the reservation. So, your card will not be charged unless you fail to show up for your Advance Dining Reservation. If your entire party misses the reservation, it will be charged. Once you arrive, you do not have to use this card to purchase the meal. You can pay for it using any method you prefer. You could choose to pay cash, use a different credit card, pay with traveler's checks, redeem Disney Dollars or Disney Gift Cards, or, like in your case, utilize Disney Dining Plan credits. Again, since you want to use your Disney Dining Plan instead of your credit card, the Cast Member will deduct the Disney Dining Plan credits from your entitlements. Happy planning and have a Magical vacation!