Disable required fields on checkout

-- HikaShop version -- : 2.3.3
-- Joomla version -- : 3.2
-- PHP version -- : ?
-- Browser(s) name and version -- : chrome
-- Error-message(debug-mod must be tuned on) -- : requires input of fileds to continue

How can we disable which fields are required? We get a red error bar at the top when we try to bypass some required fields for custom checkout.

Thanks!