  We propose a new form of entanglement called the dormant entanglement that
can be activated or destroyed by the basis choice of measurements on an
external system. The dormant entanglement without activation cannot be used as
a quantum communication resource and has reduced correlation as compared to the
Bell states. A particular form of the dormant entanglement is so weak that,
without activation, no correlation in any basis can be observed between the
entangled qubits. The dormant entanglement showcases a unique quantum behavior
that the physical description of a local system remains incomplete until the
information on all external systems entangled with the local system becomes
available. For a potential application, we propose an n-party collective
quantum communication channel that allows any 2 out of the n parties to
activate an entanglement pair with the complete consensus of all other parties.
