  We show the targeted phase-manipulation of an entangled photonic Bell state
via non-inertial motion. To this end, we place a very compact laboratory,
consisting of a SPDC source and a Sagnac interferometer, on a rotating platform
(non-inertial reference frame). The photon pairs of a $\ket{\phi}$-state are in
a superposition of co- and counter-rotation. The phase of the
$\ket{\phi}$-state is linearly dependent on the angular velocity of the
rotating platform due to the Sagnac effect. We measure the visibility and
certify entanglement with the Bell-CHSH parameter $S$. Additionally, we conduct
a partial quantum state tomography on the Bell states in a non-inertial
environment. Our experiment showcases the unitary transformation of an
entangled state via non-inertial motion and constitutes not only a switch
between a $\ket{\phi^{-}}$-state and a $\ket{\phi^{+}}$-state but also a
further experiment at the interplay of non-inertial motion and quantum physics.
