Hi Linda!
Indeed, you can opt to eat at a Quick Service dining location rather than a Table Service Restaurant for any particular meal. You will want to be sure to point out to the cashier that you are opting to do this as it may require special attention when deducting the credit from your Dining Plan.
I would definitely recommend however, that you check regularly for availability in the park you're visiting, or at a nearby resort if applicable, so that you can receive full value for that credit before you do so.
Try searching in the
Disney Dining Reservations page by 'location' and date only and see what comes up as available. Another great option where there is often greater availability is at nearby resort locations. If you're unfamiliar with the property as a whole and unsure of what your alternate options may be, feel free to contact me again with more information about your plans for that day and I'd be most pleased to give you some recommendations!
Alternatively, you can also check with the Guest Services location in the park when you arrive in the morning, and they will be happy to help you try to find something that will suit your schedule for the day.
Wishing you a Magical time at Walt Disney World Linda!
Kirsten