Changing Settlement/Region name?

Is it possible to change the name of a settlement or region?

If you just want to change the name that appears in the game you need to alter
data/text/campaign_name_regions_and_settlement_names.txt
so you have
{old_name} New Name

that works fine just to display new names in game - if you are altering a lot and doing further modding it becomes a pain to remember to look up which New Name = which old_name so you might want to change the internal names. Refer to the mapping tutorials to see which files contain region names, and make sure you change them all to exactly same thing if you are going to do that.

So leave the name in parenthesis alone, and change the other? This works for both settlement & region?

You can rename both region and settlement names, like this:
{Latium} Latium
{Rome} Rome
to
{Latium} regionX
{Rome} cityX

OK, My thanx to you both!