Sara, you have come to the right place! That is a great question and I am happy to help you out since my husband and I have used the
Rider Switch Service on many of our trips.
Several years ago, when our youngest was a baby and toddler, my husband would go with one of our oldest and then come back and go with our middle child. So, in answer to your question, it does NOT have the be different adults. There were many of times that our youngest was asleep on me or I was feeding him and could not take that second ride with one of the kids, so he would go with both.
If you follow the link I have provided above, you will also be to see a complete list of attractions that offer this service. While you wait, enjoy a snack or drink on a bench nearby. In addition to riding the attractions, I love to people watch and this provides the perfect opportunity.
Have a magical trip and feel free to stop back by the Disney Parks Moms Panel with more of your planning questions! We're here to help.
~Allison L