Rule 383.3.e.2.b

If they do not, it is removed from the chain. Example: A player controls a unit that reads in part “Once each turn, when an enemy unit dies, you may banish it.” When an enemy Recruit token dies, the triggered ability goes on the chain. If they choose not to perform the ability on finalization, it is removed from the chain. When a Stalwart Poro dies later in the turn, they can choose to trigger it then.