There is something you can do, but it's incomplete, so it won't work.
With Rainlendar_SetOption(path, name, value) you can using (e.g.):
You will need to look every calendar, compare with the one you want to change (using Rainlendar_GetCalendars), then using Rainlendar_SetOption("Calendars/Calendar" .. iNumber, "Name", strNewName) you can change the name. But, the path is getted from:
And there's no way to change "iCalendar\ Format/Default" to "iCalendar\ Format/NEWNAME" (at least what I suppose) or create, change or remove any other path.
Unless... you could persuade Rainy to add a function to rename calendars or to add/change/remove paths...