@Evan *******
the way you tell is IF you're on the small blue rectangular entry stamp that got you stamped in for a year, it means you have never extended that visa inside the country.
That's the type you have to get at least one extension based on the reason the visa was issued before you can change reasons.
OR so I have been told by immigration officers. :/ Check with your office AND definitely take your passport with you to show them you're only on an entry stamp NOT a previous extension from the O-A