This chapter discusses the possible actions one can take once they have had a surprising encounter. Sometimes, it is possible to rethink, which is to revise and restructure mental models to accommodate the new ideas provoked by the encounter. The chapter opens by describing what a "mental model" is: patterns and systems in the brain that help us understand the dynamics of the world around us. The authors stress that the mental model the reader may have is a guide, not a rule. Allowing for space outside a set model is key to imagination. The models that have been created are not reality; they are a way of understanding reality. This means not only can mental models be reconsidered without changing reality, but reality can present new information that does not have to fit into a set mental model. The chapter goes on to discuss in more detail multiple ways a mental model can be manipulated. Additionally, it discusses some ways to develop alternative models. It closes by discussing some blocks for rethinking, many involving a desire to stick to what is known and accepted, and then offers games and questions to help with the rethinking process.