When using Reaver's Row ability in chain, do you pick the target unit when the ability enters the chain or when it resolves?

Ruling: You must pick the target unit when the Reaver's Row ability is placed onto the chain, as targets must be chosen when a spell or ability is placed on the chain.

Sequence:

• Choose the target unit when placing the ability on the chain
• When the effect resolves, decide whether to actually move the chosen unit

Nuances:

• The decision to move the unit is made at resolution, but the target itself must be declared earlier when entering the chain