  We develop a Landau like theory to characterize the phase transitions in
resetting systems. Restart can either accelerate or hinder the completion of a
first passage process. The transition between these two phases is characterized
by the behavioral change in the order parameter of the system namely the
optimal restart rate. Like in the original theory of Landau, the optimal
restart rate can undergo a first or second order transition depending on the
details of the system. Nonetheless, there exists no unified framework which can
capture the onset of such novel phenomena. We unravel this in a comprehensive
manner and show how the transition can be understood by analyzing the first
passage time moments. Power of our approach is demonstrated in two canonical
paradigm setup namely the Michaelis Menten chemical reaction and diffusion
under restart.
