Two weeks ago, I was afraid that we would be a few minutes late for our ADR at 50's PT. I called Disney Dining from our resort to ask if they had anything later that evening, but they did not. I was unsure if we should cancel the ADR or try to make it (we had 5 small kids in our group, so I didn't want to rush everyone and risk someone being cranky). The CM said not to cancel if we thought we would be just a few minutes late. She said they would hold the table for 10-15 min. We decided to go and had no problems (we actually got there exactly at our ADR time or maybe a minute past).