Updating categories

-- HikaShop version -- : 2.3.3
-- Joomla version -- : 3.2.3
-- PHP version -- : 5.5.19

I imported a category using the following format:

parent_category, categories, categories_namekey
PARENT, Category Name, NAMEKEY

I had "automatically create missing categories" switched on and the category was created.

I tried to update the name of the category using the following file but it did not work:

parent_category, categories, categories_namekey
PARENT, Category Name Updated, NAMEKEY

How do I update the name of a category which I know the namekey for?