You do not need park tickets to make dining reservations. You will need tickets by the date of dinner reservation for MK.
You can start making dining reservations at 180 days out, by phone (407) WDW-DINE at 7:00 am. Or can make the reservation online starting at 6:00 am.
Please know that the full cost of this meal, per person, will be charged to your credit card when you make reservation. This is one restaurant that the top\gratuity is included in your cost.
Try to make reservation online at exactly 6:00 am. (Meaning actually logged on, etc). If you can't get, call at 7:00 am exactly.