I have worked for the same employer for 18 months. I was originally hired as a drafter, but because of my education level my employer had me doing professional level work. During that time I got a promotion into the professional track, but my overall responsibilities did not change. Does that count as a change of engagement?
I think we need some more information here. What do you mean by doing 'professional level work?' Were you doing drafting professionally? Were you doing engineering work? Professional tracks aren't the same at every company so again more information is needed before anyone can accurately weigh in.
Generally a promotion will come with relevant raises etc. However, since your responsibilities haven't changed if seems akin to being transferred from one department to another - so a paper change. Again, better information is needed here.