def METHOD_NAME():
    """
    Set the phase in the diffractometer.
        :request Content-type: application/json, an object containing
            the new phase as string, e.g. {'phase': 'Centring'}.
            [Centring, BeamLocation, DataCollection, Transfer]
        :statuscode: 200: no error
        :statuscode: 409: error
    """
    params = request.data
    params = json.loads(params)
    phase = params["phase"]
    app.beamline.diffractometer_set_phase(phase)
    return Response(status=200)