Whenever you activate an ability of an artifact, if it isn't a mana ability, you may pay. If you do, copy that ability. You may choose new targets for the copy.
7/18/2014 Activated abilities are written in the form “Cost: Effect.” Some keywords are activated abilities and will have colons in their reminder texts.
7/18/2014 A mana ability is an ability that (1) could put mana into a player’s mana pool when it resolves, (2) isn’t a loyalty ability, and (3) doesn’t target.
7/18/2014 The copy will have the same targets as the ability it’s copying unless you choose new ones. You may change any number of the targets, including all of them or none of them. If, for one of the targets, you can’t choose a new legal target, then it remains unchanged (even if the current target is illegal).
7/18/2014 If the ability is modal (that is, it says “Choose one —” or the like), the copy will have the same mode. You can’t choose a different one.
7/18/2014 If the ability has in its cost, the value of X is copied.
7/18/2014 If paying the activation cost of the ability includes sacrificing Kurkesh, the ability won’t be copied. At the time the ability is considered activated (after all costs are paid), Kurkesh is no longer on the battlefield.