title: UE4: How can i detect if an actor refrence has been destroyed in blueprints?
body: <p>In a level, I'm spwaning an actor which is designed to exist at some times and not at others. I'm spawning the actor fine, and plan to destroy it when i don't need it. But I want to make sure I'm not going to be in a state where I'm trying to act on the actor when it doesn't exist.</p>
  
  <p>I'm thinking along the lines of a c++ object pointer with new, delete and nullptr. I initailise the variable to nullptr, assign the pointer when i use new, delete the pointer when i'm done, then re-assign the variable as nullptr. This is so i can check if the pointer is valid or not by checking that it's not equal to nullptr.</p>
  
  <p>What (if anything) is the equivalent of this seemly basic concept in UE4's blueprints?</p>