I made a couple of bad assumptions. 1) That your hardwood floor was relatively level, and 2) you were referring to the corners of the room; not the open space.
This is a problem. The floor should be sanded 'level' and smooth, equally in all parts. However, if you have such a 'difference' in height in the spance of the room, yes, you can use the corner sander for this job. BUT, you'll end up with an unlevel floor. The only time I've seen it where adjoining boards are 'drastically' out-of-line is where there's no tongue or a completely broken one. The purpose of the tongue is to keep the boards 'level' and together. If you can't level the boards/strips directly, you have a few choices, none of which I truely recommend w/o seeing the problem. 1) Do nothing. If you do nothing, you'll have a color/finish difference. 2) Sand with the drum until they're level. Depending on how much wood is on the strip/plank, you may sand right down to the tongue w/o geting the rough finish you want. At that point, you'll end up trying Option 3. 3) Sand by hand or with a corner sander ONLY the area that's not getting sanded by the drum. This creates a 'lip' which, well, not what you want.
To determine how much wood you might be able to sand, look at the end of a strip/plank where it runs into, say, a heating vent. Use a mirror to see. If you notice the most recent sanding only leave you with about 1/8", well, you may get to the tongue (and/or the nails in the tongue) a LOT quicker than you want. At that point, you'll have to cover up any 'mistakes' by doing step 3). At some point, you may have to call in a pro to finish the sanding part of the job (if that's all you need him to do.) If it comes to this, be very flexible. You're probably not going to be one of his higher paying customers.