  We argue that given holographic CFT$_1$ in some state with a dual spacetime
geometry M, and given some other holographic CFT$_2$, we can find states of
CFT$_2$ whose dual geometries closely approximate arbitrarily large causal
patches of M, provided that CFT$_1$ and CFT$_2$ can be non-trivially coupled at
an interface. Our CFT$_2$ states are "dressed up as" states of CFT$_1$: they
are obtained from the original CFT$_1$ state by a regularized quench operator
defined using a Euclidean path-integral with an interface CFT$_1$ CFT$_2$ and
CFT$_1$. Our results are consistent with the idea that the precise microscopic
degrees of freedom and Hamiltonian of a holographic CFT are only important in
fixing the asymptotic behavior of a dual spacetime, while the interior
spacetime of a region spacelike separated from a boundary time slice is
determined by more universal properties (such as entanglement structure) of the
quantum state at this time slice. Our picture requires that low-energy
gravitational theories related to CFTs that can be non-trivially coupled at an
interface are part of the same non-perturbative theory of quantum gravity.
