Well, if you get a rare, a sword in this case, and it had a perfect Fortitude pommel(+30 Health) then you could try to salvage it using a Expert Salvage Kit (sometimes the rares that have perfect mods also have perfect innate mods also, like +15% damage when health is over 50%, DON'T SALVAGE IT! See if you can get a PC for it first!)
IF you succesfully salvage the Fortitude mod, (sometimes it doesn't salvage and you just get some stupid crafting materials ><) then you can apply it to any other sword, in this case, your Flamberge.
Hope that cleared up your question
