The cast members recognize "switch" or "switchy". (We learned that cast members don't understand "baby swap" or "parent swap".) For Japanese speakers, they may relay verbal instructions about where to go and who to talk to. For English speakers like my family, it's a very welcome lesson in Japanese customer service:
They carefully explain that someone needs to enter the ride queue while the other person stays with the child and holds the "rider switch" ticket (good for up to 4 guests). When the first rider exits the attraction and meets up with the non-riders, the non-riders (and lucky friends) go to the attraction greeter and present the ticket. One cast member will escort the group directly to the loading platform (going through some interesting back-stage areas). Japanese speakers are instructed to "go to the exit and show this ticket to the cast member." But Disney does not trust English-speakers to understand such complicated instructions, so we always got an escort.

It's at least twice as fast as using FastPass. It's a wonderful service -- it felt like a VIP tour. Note: I described how it works for Splash Mountain, Big Thunder Mountain Railroad, Space Mountain, Indiana Jones and the Temple of the Crystal Skull, and Raging Spirits. For Tower of Terror, "switchy" users still experience the entire pre-show.
For Star Tours, no tickets are issued and everyone enters the queue together. At the loading area, the waiting parent-and-child stay behind while the non-waiting parent rides the simulator. At the end of the ride, the riding parent is supposed to return and take the child through the ride vehicle to the exit. (Cast members had to chase down my wife, who forgot to return for our baby. Very funny!)