arcgis 10.0 - Change Symbology of layers from within ArcMap

In an active ArcMap session - I want to change the symbology of a layer which is repeated multiple times in the mxd. Can I do this?

The basic code I have for getting the layers is below. This is running within ArcMap (not as a .py script)

myMXD = arcpy.mapping.MapDocument("Current")
lstDataFrames=arcpy.mapping.ListDataFrames(myMXD)
lstLayers=arcpy.mapping.ListLayers(myMXD)

hazardLayer=arcpy.mapping.ListLayers(myMXD,'*Haz*')

allFrames=arcpy.mapping.ListDataFrames(myMXD)

for dataFrame in allFrames:
    myMXD.activeView=dataFrame

    for mapLayer in hazardLayer:
        mapLayer.visible=False

This just changes the visibility to off...can I change the color for example to some RGB value?

Answer

First create a default layer file to use as a template then:

myMXD = arcpy.mapping.MapDocument("Current")
lstDataFrames=arcpy.mapping.ListDataFrames(myMXD)
lstLayers=arcpy.mapping.ListLayers(myMXD)


hazardLayer=arcpy.mapping.ListLayers(myMXD,'*Haz*')

allFrames=arcpy.mapping.ListDataFrames(myMXD)

for dataFrame in allFrames:
     myMXD.activeView=dataFrame
     for mapLayer in hazardLayer:
         arcpy.ApplySymbologyFromLayer_management(mapLayer, r"C:\TemplateLayers\HazardTemplate.lyr")