I would say yes based on AM pg 6; under Attacks it says: "It IS legal to
CHANGE to an attack option when your turn to act comes, if you did not move
more than that option allows. For instance, if a figure stood still during
movement, intending to "change weapons," and an enemy moved into one of his
front hexes to attack, then the first figure could change to option I (a) and
attack." Although this is written as pertaining to changing TO an attack
option, I do not see why it would not apply to the reverse or to any
other legal action...of course, I've been wrong before. -Rich