Change in currency codes

SOLVED

Right now my organization is using two currency codes to designate the same currency, we have US and USD being used in the system. Third party software uses US and this is why it exists. I suggest that we stop using USD by making it inactive. As we know there is no switch in Sage to do this so what would be the best method to get users to stop using USD? Would it also be worth changing in the tables the fields marked USD to US or is there absolutely no cost benefit.