  The classical black hole spacetime is modified semiclassically, depending
strongly on the choice of the quantum states. In particular, for the Boulware
state the spacetime often takes a wormhole structure mimicking closely a
spacetime with a horizon. In this paper, in the context of the two-dimensional
dilaton RST model, we consider all possible important interplays between the
Hartle-Hawking, Unruh and Boulware quantum states. Special attention is given
to the hybrid states made up of quantum fields either in the Hartle-Hawking or
Unruh states, and some non-physical fields (with the wrong sign in the kinetic
term in the action) in the Boulware state. We present a detailed analysis of
the semiclassical geometry in all these cases paying attention to the presence
or absence of horizons, curvature singularities and to the geodesic
completeness of the spacetime. In the space of parameters specifying the
generic quantum state, we find a wide domain (with dominating non-physical
fields) where the semiclassical geometry represents a geodesically complete,
asymptotically flat causal diamond, free of horizon or curvature singularity.
However, a distant observer still finds Hawking radiation at asymptotic
infinity. In the Unruh-Boulware hybrid state solution, we find that the energy
flux at asymptotic infinity receives important corrections from its thermal
behavior, leading to information recovery as we go from early to late retarded
times. As a result, the corresponding entropy shows a typical Page curve
bahavior.
