  In this work we study a model of opinion dynamics considering
activation/deactivation of agents. In other words, individuals are not static
and can become inactive and drop out from the discussion. A probability $w$
governs the deactivation dynamics, whereas social interactions are ruled by
kinetic exchanges, considering competitive positive/negative interactions.
Inactive agents can become active due to interactions with active agents. Our
analytical and numerical results show the existence of two distinct
nonequilibrium phase transitions, with the occurrence of three phases, namely
ordered (ferromagnetic-like), disordered (paramagnetic-like) and absorbing
phases. The absorbing phase represents a collective state where all agents are
inactive, i.e., they do not participate on the dynamics, inducing a frozen
state. We determine the critical value $w_c$ above which the system is in the
absorbing phase independently of the other parameters. We also verify a
distinct critical behavior for the transitions among different phases.
