Non-immigrants come to the country for many different reasons, and those reasons are subject to change. Sometimes, paperwork also needs to be changed in accordance. However, there are a few situations in which changing that paperwork is impossible due to the category that the non-immigrant was initially registered under.
According to the United States Citizenship and Immigration Services, some types of non-immigrant visa categories can be changed or renewed but there are other categories that are resistant to change. Some only have restrictions, but there are a few in which a request cannot be made at all. The following categories do not allow for requests to be made: