The aim of a nomination and change round is to harvest the wisdom from the group on who might be qualified to fill a role. In that way, it is ok to pass. On the other hand, sometimes selection processes put circles into the slightly uncomfortable position of having to pick one person among a lot of equally qualified people. In an extreme case, everyone in the circle might pass in the nomination round. If that were to happen, then picking someone would be extra hard and the process would be slowed down. Also, people might pass because they are holding back information because they might feel intimidated because of some internal power dynamics.
Those could be reasons for a facilitator to not let anyone pass in a nomination or change round. Ideally, the facilitators reveal transparently what led them to choose either one.
For more information, check out our handbook Many Voices One Song section 3.6