Change Job during battle?

[JadeKnightblazer]

Wondering if its possible to change a Job class during battle. Be like Equip Change, but jobs rather then items.  Or even if its possible to open the R/S/M screen during a battle, adding / removing, swapping.

[Nyzer]

Job changing is done in WORLD.BIN, whereas battles use BATTLE.BIN. Basically, the game is reading from an entirely different sector, and I don't know if there's any way to make it call anything from the other.