  Entanglement is one of the key feature of quantum world and any entanglement
measure must satisfy some basic laws. Most important of them is the invariance
of entanglement under local unitary operations. We show that this is no longer
true with local ${\cal {PT}}$ symmetric unitary operations. If two parties
share a maximally entangled state, then under local ${\cal {PT}}$ symmetric
unitary evolution the entropy of entanglement for pure bipartite states does
not remain invariant. Furthermore, we show that if one of the party has access
to ${\cal {PT}}$-symmetric quantum world, then a maximally entangled state in
usual quantum theory appears as a non-maximally entangled states for the other
party. This we call as the "entanglement mismatch" effect which can lead to the
violation of the no-signaling condition.
