Change language

Living in Austria I bought NAV in one of the shops here few years ago. The product language is registered to German because it's bought here. When installing the first time I recall an option to choose the language. I don't see that option anymore. Last year the updating process was a nightmare so I don't want to go thru that process again. Everything on my computer is in English and I would like to be able to have NAV in English as well. How can I change the product language version in my account from German to English permanently?