Switch

Someone who enjoys both dominant and submissive roles, either with different partners or at different times.

A switch is a person who moves between dominant and submissive roles rather than identifying with just one. Some switch depending on their partner, some depending on their mood, and some within a single scene. Being a switch offers a broad perspective, since the person understands both sides of a power exchange. There is nothing indecisive about it: it is simply a wider range of what someone enjoys.