Hi Dylan! Thanks for bringing your question to planDisney! Your question is the sign of a good planner! Planning park days and dining reservations is an important part of any Disney vacation!
Park reservations can be made for one park per day using the
Disney Park Pass System. Under current operating conditions, your example of visiting Magic Kingdom Park during the day and then EPCOT for dinner at
Le Cellier Steakhouse would not be possible.
Dylan, one possible work around that might help is to know that you can enter, exit, and re-enter the same park in the same day. So you could visit EPCOT during the daytime, return to your resort for an afternoon break, and then return to EPCOT to enjoy a delicious dinner at Le Cellier Steakhouse which, by the way, is a superb choice! I hope this is helpful as you go about planning your magical vacation! Come back to visit planDisney as you continuing your planning!
Hakuna Matata! Jonathan G.