  We propose and experimentally demonstrate a transformation of two EPR photon
pairs distributed among three parties into a three-photon W state using local
operations and classical communication. We then characterize the final state
using quantum state tomography on the three-photon state and on its marginal
bipartite states. The fidelity of the final state to the ideal W state is
$0.778\pm 0.043$ and the expectation value for its witness operator is
$-0.111\pm 0.043$ implying the success of the proposed local transformation.
