Spells with casting times > 1 second: when do you pick the subject?

[Michael Thayne]

Suppose you start casting Daze, which has a 2 second casting time. Then one of your allies kills the target you were initially planning on hitting with the spell. Can you switch to another target on your following turn, or do you have to abort your casting and try again?

[Anders]

I'd allow them to switch. It's just a hassle otherwise.

[Kromm]

You pick the target when you roll the dice, same as for anything else that has a "target." Casting is not attacking, but its physical combat analog is a bunch of Ready maneuvers to prepare a weapon followed by an Attack maneuver to use it, not a series of Aim or Evaluate maneuvers to watch a specific foe followed by an Attack maneuver on that one foe. Concentrate is mental Ready, not mental Aim or Evaluate.