  We experimentally demonstrate the nonlocal reversal of a partial-collapse
quantum measurement on two-photon entangled state. Both the partial measurement
and the reversal operation are implemented in linear optics with two displaced
Sagnac interferometers, which are characterized by single qubit quantum process
tomography. The recovered state is measured by quantum state tomography and its
nonlocality is characterized by testing the Bell inequality. Our result will be
helpful in quantum communication and quantum error correction.
