Even if you wish to obtain an Engineer/Specialist in Humanities/International Services visa but have not graduated from either a university or a professional training college, you can still be eligible if you have a vocational experience in your field for a certain amount of years.
Some people, for example, work as an interpreter under a Designated Activities visa, more specifically as a working holiday, that experience can be a part of that vocational experience required for an Engineer/Specialist in Humanities/International Services visa.
Some people, on the other hand, might receive permission for activities other than that permitted under the current status as a student and work as an interpreter, but that experience cannot be a part of that vocational experience.
”Switching from a working holiday to a working visa” is a complicated process. Please feel free to contact me if you are interested in switching from a working holiday to a working visa.