How to Revert a particle system

Questions & Answers
1

I would like to return to the previous update from shuriken a particle system, I do not know how.
What should I do?
I am a beginner.
Is grateful if you would tell me.

2

Create an empty game object.

Then got to Component > Effects > Legacy Particles and add the following to the empty game object: Particle Animators, Particle Render and finally the Ellipsoid Particle Emitter.

Now you should see the old particle system.

Got this from the Reference Manual.