It's quite easy: say you're offered seat 217 on row 52 and you would rather have an aisle seat higher up- just put in a high number for the amount of tickets you want (say 17 to cover an entire row in the 202 PTS allocation). The system will attempt to give you the next contiguous block of 17 seats, which will be the next completely empty row. Pick the seat you want, the aisle seat say, and delete the other seats. If it can't allocate you that many seats together, then just reduce the number each time until it finds a block of empty seats and do the same thing as above. Of course, if the system was in any way decent you would be able to pick the seat and row you want, but that's another story...