  We show that the only way of changing the framing of a link by ambient
isotopy in an oriented $3$-manifold is when the manifold has a properly
embedded non-separating $S^2$. This change of framing is given by the Dirac
trick, also known as the light bulb trick. The main tool we use is based on
McCullough's work on the mapping class groups of $3$-manifolds. We also relate
our results to the theory of skein modules.
