  We demonstrate in a superconducting qubit the conditional recovery
("uncollapsing") of a quantum state after a partial-collapse measurement. A
weak measurement extracts information and results in a non-unitary
transformation of the qubit state. However, by adding a rotation and a second
partial measurement with the same strength, we erase the extracted information,
effectively canceling the effect of both measurements. The fidelity of the
state recovery is measured using quantum process tomography and found to be
above 70% for partial-collapse strength less than 0.6.
