There is a well-known way to describe a link diagram as a (signed) plane graph,
called its Tait graph. This concept was recently extended, providing a way to
associate a set of embedded graphs (or ribbon graphs) to a link diagram.
While every plane graph arises as a Tait graph of a unique link diagram, not
every embedded graph represents a link diagram. Furthermore, although a
Tait graph describes a unique link diagram, the same embedded graph can
represent many different link diagrams. One is then led to ask which embedded
graphs represent link diagrams, and how link diagrams presented by the
same embedded graphs are related to one another. Here we answer these
questions by characterizing the class of embedded graphs that represent link
diagrams, and then using this characterization to find a move that relates
all of the link diagrams that are presented by the same set of embedded
graphs.