So, imagine a brand new player, just wants to try the game out, accidentally takes a name used by a veteran in another server once upon a time... This player deserves to be abused or refused from taking this name even though no one already took it on this particular server?
There is no way to tell if someone has taken a name to deliberately spite another player at the time the character is created. The OP's request is not workable as it stands...
However... I do see an opportunity for the server team to make a bit of cash by charging players to reserve their names in advance!