I'm pretty sure giving it another name would be difficult you would probably have to duplicate the skill in the source .
Each skill get's it's name from skillnametable.txt
Such as:
// Lord_Knight Skills \\
LK_AURABLADE#Aura_Blade#
LK_BERSERK#Berserk#
LK_CONCENTRATION#Concentration#
Changing that would change the name of the entire skill so it change it for LK as well.
So I guess the only way would to too make a duplicate then make a entire new skill via rA's source.
With a different ID and such then add another line in skillnametable.txt
But you can give concentration to another class easily:
JOB_ID_HERE,357,5,4,5,55,5,63,1,0,0,0,0 //LK_CONCENTRATION#Concentration#
under another job in skill_tree
For example let's give Concentration to High Priests.
//HighPriest
4009,357,5,4,5,55,5,63,1,0,0,0,0 //LK_CONCENTRATION#Concentration#
4009,1,9,0,0,0,0,0,0,0,0,0,0 //NV_BASIC#Basic Skill#
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