The capability to edit the database is one of the major differences between Version 1.0 and Version 2.0 of Town Chooser.  Choosing the File Menu and then clicking the Edit Cities Database option brings up the Edit Town Names Window.

Notice there are ten buttons below the Town Name textbox.  The Town Name textbox contains the name of the current town in the database.  This can be changed with the various Move buttons that are explained under the Moving around the database topic.  You'll also notice that you can Find a specific town, Add a new town, and Delete a town using the respective buttons.  Instructions can be found in the Status Bar and by observing the various Tool Tips that are available for the different buttons.