Hiya Jenean! Thanks for stopping by planDisney with your question! Oh boy! It seems like you are headed to
Walt Disney World today! I'm sure you are excited to get the day started and have a magical Disney visit!
To get to your question, it will depend on what reservation you are referring to. For
theme park reservations, you can arrive at the park at any time of the day and be allowed entry. Park reservations along with a valid park ticket are required for entry each day. There is no specific time that you need to arrive on your park day, so if you are taking a little extra time to get ready or only want to go for the evening, the choice is yours.
If you are referring to
Disney Genie+ or Individual Lightning Lane reservations, you will need to show up to the selected attraction within the one-hour arrival window that is awarded to you. There should be a 15-minute grace period once the time slot expires, but I would not count on this every time. If you know you are not going to be able to make it, I would stop by a Guest Relations booth, which is located throughout all of the parks, and speak to a Cast Member for assistance. They may be able to help out if there were extending circumstances.
For
Advanced Dining Reservations, if you know ahead of time that you are going to be late, I would suggest accessing your My Disney Experience account to try and modify it to a later time. If there is nothing available, I would still head over to the restaurant upon arrival to see if they can accommodate your party for a later time. There are instances when cancelations occur and the table service restaurant can adjust their seating. I would not necessarily count on this, but it is worth the attempt.
Jenean, I hope you have an amazing time!
Stop back and see us again at planDisney!
Have a magical day!
Greg