What happens when you copy a spell with targets — do you choose new targets for the copy?

When a spell or ability creates a copy of a spell on the stack, the copy is created with the same choices made for the original — including modes, X values, and targets (CR 707.10). However, the player who controls the copy may then choose new targets for it. This is not optional in the sense that you may change any or all targets, change none, or mix and match.

The rule that governs this is CR 707.10: "A copy of a spell or ability becomes part of the stack, has the same characteristics as the original, and can be affected by anything that affects the original... The controller of the copy may choose new targets for the copy." Importantly, any targets you keep must still be legal targets at the time you make your choices.

This means if you copy a spell and want to redirect it to a different creature, you can — but you could also leave all targets the same. You cannot, however, choose an illegal target (e.g., a creature with hexproof that you don't control) even if the original spell was legally targeting something else.

Example: Your opponent casts Lightning Bolt targeting your creature. You cast Reverberate to copy it. The copy starts targeting your creature, but you may choose new targets — you redirect the copy to hit your opponent's face for 3 damage instead, while the original still hits your creature.

Note that if a copy is created by an ability that itself says "you may choose new targets," the same CR 707.10 logic applies. Some effects that copy spells have additional restrictions on whether targets can be changed, so always read the specific card text carefully.