As long as you have your ducks in a row with flights that have R availability and can get an agent who is willing to spend some time and work with a supervisor, it should work. Just be prepared for a lot of agravation.
I would still try to do it mysef online. When I did a test (TPA-EZE-TPA) where I knew R seats were available, it let me go all the way to the last screen where it would ticket, so I backed off. It may be that I was only looking at 1 seat in that scenario.