The card has this text: "Resolve one of your dice as if it were showing melee damage (X) (it keeps its original value) ."
Can you use it on something already showing the Melee symbol? For instance on a Melee Modifier side with the +.... Seems to me, based on my understanding of the RR, that a Melee Modifier side is different than a side "showing melee damage (X)" as per the text on Now You Will Die and that this will work....
Just thought I'd ask first though....