Universal Studios Hollywood Child Switch Program - Explainer Video (2017):
What is child switch? How does it work?
At each of Universal Studios Hollywood's attractions, they offer a “child switch” program. If any child in your party cannot ride an attraction, one or two adults can wait with the child in the attraction’s Child Switch room.
When the rest of your party returns, they switch with those who were waiting with the child, without having to wait in line again.
Please ask any team member at the entrance of the attraction and they will be happy to assist you.