There is a class feature for spores druids called Fungal infestation, and in the rules it is stated:
If a beast or humanoid that is Small or Medium dies within 10 feet of you, you can use your reaction to animate it, causing it to stand up immediately with 1 hit point. The creature uses the zombie statistics. It remains animate for 1 hour, after which time it collapses and dies.
So, if a bandit dies within 10 feet of a druid of spores, and the druid doesn’t revive him (already spent reaction on the turn or whatever) can he use the reaction to revive next turn?