I don't know if it still is written this way, but long ago in the congrats letter it would basically state congrats you have been awarded a Type # scholarship for a tech major, or a non-tech major.
If it states a tech major than they expect you to major in a tech degree and if you try to change to a non-tech than they may not allow you to keep the scholarship. If it says a non-tech major, but you want to change it to a tech it will be easier to switch.
~ It is not that difficult to change from let's say Chem E to EE, but you still need their approval. However changing from Chem E to business, well you probably have a higher chance of finding big foot. There's a chance, but it is rare.
~ As Thunderbolt stated the intended major must be on their approved list.
It is important to note that the reason that it is more akin to locking you into a tech or non-tech field is that not every college carries every major on the list. The scholarship is tied to the cadet and not the school. IE College A and B offer History, but only College A offers Poli Sci. Let's say you only get into B. Well than you will need to change your major to an approved degree since they do not offer Poli Sci.